Heat-assisted magnetic recording head including internal mirrors of first and second inclined surfaces

ABSTRACT

A heat-assisted magnetic recording head has an internal mirror that includes a reflecting film support body and a reflecting film. The internal mirror reflects light that comes from above a waveguide so that the reflected light travels through the waveguide toward a medium facing surface. The reflecting film support body includes first and second inclined surfaces. The reflecting film includes first and second portions that are located on the first and second inclined surfaces, respectively. The step of forming the reflecting film support body includes two-taper etching operations to be performed on an initial support body.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat-assisted magnetic recording headfor use in heat-assisted magnetic recording where a recording medium isirradiated with near-field light to lower the coercivity of therecording medium for data recording.

2. Description of the Related Art

Recently, magnetic recording devices such as a magnetic disk drive havebeen improved in recording density, and thin-film magnetic heads andmagnetic recording media of improved performance have been demandedaccordingly. Among the thin-film magnetic heads, a composite thin-filmmagnetic head has been used widely. The composite thin-film magnetichead has such a structure that a reproducing head including amagnetoresistive element (hereinafter, also referred to as MR element)for reading and a recording head including an induction-typeelectromagnetic transducer for writing are stacked on a substrate. In amagnetic disk drive, the thin-film magnetic head is provided in a sliderwhich flies slightly above the surface of the magnetic recording medium.

To increase the recording density of a magnetic recording device, it iseffective to make the magnetic fine particles of the recording mediumsmaller. Making the magnetic fine particles smaller, however, causes theproblem that the magnetic fine particles drop in the thermal stabilityof magnetization. To solve this problem, it is effective to increase theanisotropic energy of the magnetic fine particles. However, increasingthe anisotropic energy of the magnetic fine particles leads to anincrease in coercivity of the recording medium, and this makes itdifficult to perform data recording with existing magnetic heads.

To solve the foregoing problems, there has been proposed a techniqueso-called heat-assisted magnetic recording. This technique uses arecording medium having high coercivity. When recording data, a magneticfield and heat are simultaneously applied to the area of the recordingmedium where to record data, so that the area rises in temperature anddrops in coercivity for data recording. The area where data is recordedsubsequently falls in temperature and rises in coercivity to increasethe thermal stability of magnetization.

In heat-assisted magnetic recording, near-field light is typically usedas a means for applying heat to the recording medium. A known method forgenerating near-field light is to irradiate a plasmon antenna, which isa small piece of metal, with laser light. The plasmon antenna has anear-field light generating part which is a sharp-pointed part forgenerating near-field light. The laser light applied to the plasmonantenna excites surface plasmons on the plasmon antenna. The surfaceplasmons propagate to the near-field light generating part of theplasmon antenna, and the near-field light generating part generatesnear-field light based on the surface plasmons. The near-field lightgenerated by the plasmon antenna exists only within an area smaller thanthe diffraction limit of light. Irradiating the recording medium withthe near-field light makes it possible to heat only a small area of therecording medium.

In general, the laser light to be used for generating the near-fieldlight is guided through a waveguide that is provided in the slider tothe plasmon antenna that is located near the medium facing surface ofthe slider. Possible techniques of placement of a light source thatemits the laser light are broadly classified into the following two. Afirst technique is to place the light source away from the slider. Asecond technique is to fix the light source to the slider.

The first technique is described in U.S. Patent Application PublicationNo. 2006/0233062 A1, for example. The second technique is described inU.S. Patent Application Publication No. 2008/0055762 A1 and U.S. PatentApplication Publication No. 2008/0002298 A1, for example.

The first technique requires an optical path of extended lengthincluding such optical elements as a mirror, lens, and optical fiber inorder to guide the light from the light source to the waveguide. Thiscauses the problem of increasing energy loss of the light in the path.The second technique is free from the foregoing problem since theoptical path for guiding the light from the light source to thewaveguide is short.

The second technique, however, has the following problem. Hereinafter,the problem that can occur with the second technique will be describedin detail. The second technique typically uses a laser diode as thelight source. Laser light emitted from the laser diode can be madeincident on the waveguide by a technique described in U.S. PatentApplication Publication No. 2008/0055762 A1, for example. Thispublication describes arranging the laser diode with its emission partopposed to the incident end of the waveguide so that the laser lightemitted from the emission part is incident on the incident end of thewaveguide without the intervention of any optical element. According tothis technique, the laser diode is arranged so that the longitudinaldirection of the laser diode, i.e., the direction of the optical axis ofthe laser light to be emitted from the emission part, is perpendicularto the end face of the slider where the incident end of the waveguide islocated. In such a case, the laser diode needs to be positioned withhigh precision so that the optical axis of the laser light emitted fromthe emission part will not tilt with respect to the optical axis of thewaveguide. If the optical axis of the laser light emitted from theemission part tilts with respect to the optical axis of the waveguide,the laser light may fail to be delivered to the plasmon antenna withsufficient intensity. When the laser diode is to be arranged so that thelongitudinal direction of the laser diode is perpendicular to the endface of the slider where the incident end of the waveguide is located,however, there is a problem that the longitudinal direction of the laserdiode can easily tilt with respect to the direction perpendicular to theend face of the slider where the incident end of the waveguide islocated, and it is thus difficult to align the laser light with thewaveguide.

The laser light emitted from a laser diode may be made incident on thewaveguide by other techniques. For example, as described in U.S. PatentApplication Publication No. 2008/0002298 A1, the laser diode may bearranged with its emission part opposed to the surface of the slider onthe trailing side so that the laser light emitted from the emission partis incident on the waveguide from above. This technique facilitates thealignment of the laser light with the waveguide.

U.S. Patent Application Publication No. 2008/0002298 A1 describes amagnetic head that includes a diffraction grating in its slider. Thediffraction grating diffracts laser light that is emitted from a laserdiode and enters the slider from above the slider, so that thediffracted laser light travels through the waveguide toward the mediumfacing surface. As a means for changing the traveling direction of thelaser light, however, a mirror may be more advantageous than thediffraction grating because of its simpler structure. Providing aninternal mirror in the slider is therefore conceivable, the internalmirror being intended for reflecting laser light coming from above thewaveguide so that the reflected laser light travels through thewaveguide toward the medium facing surface.

A method of fabricating such an internal mirror will now be discussed.In a possible method of fabricating the internal mirror, for example, anetching mask of photoresist is formed on an insulating layer of aluminaor the like, and the insulating layer is taper-etched by reactive ionetching to provide the insulating layer with an inclined surface. Areflecting film of metal is then formed on the inclined surface by vapordeposition, sputtering, etc. The surface of the reflecting film servesas the reflecting surface for reflecting the laser light.

Hereinafter, a description will be given of problems that are associatedwith the foregoing method of fabricating the internal mirror. Whentaper-etching an insulating layer, the etching rate is typically lowerthan when etching the insulating layer perpendicularly. Given the sameetching depth, an etching mask of greater thickness is therefore neededto taper-etch the insulating layer than when etching the insulatinglayer perpendicularly. Thicker etching masks, however, can lose theirshape more easily due to plasma during etching. The foregoing method offabricating the internal mirror therefore has the problem that it isdifficult to form a plane inclined surface when fabricating an internalmirror having a reflecting surface of large dimension in the depthdirection in particular, because of the deformation of the etching maskduring the etching of the insulating layer for the purpose of formingthe inclined surface. If the inclined surface is non-plane, thereflecting surface also becomes non-plane. This results in a drop in theamount of laser light that is reflected by the reflecting surface andtravels in a desired direction, thereby causing the problem of low useefficiency of the laser light for generating near-field light.

OBJECT AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a heat-assistedmagnetic recording head including an internal mirror for reflectinglight that comes from above a waveguide and is used to generatenear-field light so that the reflected light travels through thewaveguide, the heat-assisted magnetic recording head being capable ofpreventing a drop in use efficiency of the light due to the internalmirror, and to provide a method of manufacturing such a heat-assistedmagnetic recording head.

A heat-assisted magnetic recording head of the present inventionincludes: a medium facing surface that faces a recording medium; amagnetic pole that has an end face located in the medium facing surface,for producing a recording magnetic field for recording data on therecording medium; a waveguide that allows light to propagatetherethrough; a near-field light generating element having a near-fieldlight generating part located in the medium facing surface, a surfaceplasmon being excited based on the light propagating through thewaveguide, the surface plasmon propagating to the near-field lightgenerating part, the near-field light generating part generatingnear-field light based on the surface plasmon; an internal mirror; and asubstrate having a top surface.

In the heat-assisted magnetic recording head of the present invention,the magnetic pole, the waveguide, the near-field light generatingelement, and the internal mirror are located above the top surface ofthe substrate. The internal mirror includes a reflecting film supportbody, and a reflecting film supported by the reflecting film supportbody. The internal mirror reflects light that comes from above thewaveguide so that the reflected light travels through the waveguidetoward the medium facing surface.

The reflecting film support body includes a first inclined surface and asecond inclined surface, each of the first and second inclined surfaceshaving a front end and a rear end. The rear end of the first inclinedsurface is located farther from the medium facing surface and fartherfrom the top surface of the substrate than is the front end of the firstinclined surface. The front end of the second inclined surface islocated farther from the medium facing surface and farther from the topsurface of the substrate than is the front end of the first inclinedsurface. The rear end of the second inclined surface is located fartherfrom the medium facing surface and farther from the top surface of thesubstrate than are the rear end of the first inclined surface and thefront end of the second inclined surface. With respect to a virtualplane that includes the first inclined surface, the second inclinedsurface is offset in a direction perpendicular to the first inclinedsurface.

The reflecting film includes a first portion located on the firstinclined surface, and a second portion located on the second inclinedsurface. The first portion includes a first reflecting surface having afront end and a rear end. The second portion includes a secondreflecting surface having a front end and a rear end. The rear end ofthe first reflecting surface is located farther from the medium facingsurface and farther from the top surface of the substrate than is thefront end of the first reflecting surface. The front end of the secondreflecting surface is located farther from the medium facing surface andfarther from the top surface of the substrate than is the front end ofthe first reflecting surface. The rear end of the second reflectingsurface is located farther from the medium facing surface and fartherfrom the top surface of the substrate than are the rear end of the firstreflecting surface and the front end of the second reflecting surface.With respect to a virtual plane that includes the first reflectingsurface, the second reflecting surface is offset in a directionperpendicular to the first reflecting surface.

In the heat-assisted magnetic recording head of the present invention,each of the first and second reflecting surfaces may form an angle of45° with respect to a direction perpendicular to the top surface of thesubstrate.

In the heat-assisted magnetic recording head of the present invention,the first and second inclined surfaces may be arranged so as not tooverlap each other as seen in the direction perpendicular to the topsurface of the substrate.

In the heat-assisted magnetic recording head of the present invention,the reflecting film may further include a coupling portion that couplesthe first portion to the second portion. The coupling portion mayinclude a coupling surface that couples the first reflecting surface tothe second reflecting surface. In this case, an angle formed by thecoupling surface with respect to the direction perpendicular to the topsurface of the substrate may be greater or smaller than an angle formedby each of the first and second reflecting surfaces with respect to thedirection perpendicular to the top surface of the substrate.

In the heat-assisted magnetic recording head of the present invention,the first and second inclined surfaces may be arranged so as to overlapeach other as viewed in the direction perpendicular to the top surfaceof the substrate.

In the heat-assisted magnetic recording head of the present invention,the near-field light generating element may have an outer surface, theouter surface including: a first end face that is located in the mediumfacing surface; a second end face that is farther from the medium facingsurface; and a coupling part that couples the first end face to thesecond end face. The first end face may include the near-field lightgenerating part. In this case, a length of the near-field lightgenerating element in a direction perpendicular to the medium facingsurface may be greater than a length of the first end face in thedirection perpendicular to the top surface of the substrate, and thewaveguide may have an outer surface including an opposed portion that isopposed to a part of the coupling part. In this case, the outer surfaceof the waveguide may include a front end face that is closer to themedium facing surface, a rear end face that is farther from the mediumfacing surface, and a top surface that is farther from the top surfaceof the substrate. The rear end face may be in contact with the first andsecond reflecting surfaces. The light that comes from above thewaveguide may be reflected by the first and second reflecting surfacesafter entering the waveguide from the top surface of the waveguide.

The heat-assisted magnetic recording head of the present invention mayfurther include a laser diode that emits the light to be reflected bythe internal mirror.

A heat-assisted magnetic recording head that is manufactured by amanufacturing method of the present invention includes: a medium facingsurface that faces a recording medium; a magnetic pole that has an endface located in the medium facing surface, for producing a recordingmagnetic field for recording data on the recording medium; a waveguidethat allows light to propagate therethrough; a near-field lightgenerating element having a near-field light generating part located inthe medium facing surface, a surface plasmon being excited based on thelight propagating through the waveguide, the surface plasmon propagatingto the near-field light generating part, the near-field light generatingpart generating near-field light based on the surface plasmon; aninternal mirror; and a substrate having a top surface.

In the heat-assisted magnetic recording head manufactured by themanufacturing method of the present invention, the magnetic pole, thewaveguide, the near-field light generating element, and the internalmirror are located above the top surface of the substrate. The internalmirror includes a reflecting film support body and a reflecting film,the reflecting film support body including at least one layer, thereflecting film being supported by the reflecting film support body. Theinternal mirror reflects light that comes from above the waveguide sothat the reflected light travels through the waveguide toward the mediumfacing surface.

The manufacturing method for the heat-assisted magnetic recording headof the present invention includes the steps of forming the magneticpole; forming the internal mirror; forming the waveguide; and formingthe near-field light generating element.

The step of forming the internal mirror includes the step of forming thereflecting film support body and the step of forming the reflectingfilm. The reflecting film support body includes a first inclined surfaceand a second inclined surface, each of the first and second inclinedsurfaces having a front end and a rear end. The rear end of the firstinclined surface is located farther from the medium facing surface andfarther from the top surface of the substrate than is the front end ofthe first inclined surface. The front end of the second inclined surfaceis located farther from the medium facing surface and farther from thetop surface of the substrate than is the front end of the first inclinedsurface. The rear end of the second inclined surface is located fartherfrom the medium facing surface and farther from the top surface of thesubstrate than are the rear end of the first inclined surface and thefront end of the second inclined surface.

The step of forming the reflecting film support body includes the stepsof forming an initial support body that is intended to undergo theformation of the first and second inclined surfaces therein later tothereby become the reflecting film support body; and etching the initialsupport body so that the first and second inclined surfaces are formedin the initial support body and the initial support body thereby becomesthe reflecting film support body.

The step of etching the initial support body includes: the step offorming a first etching mask that covers a part of the initial supportbody except an area where the first inclined surface is to be formedlater as viewed in the direction perpendicular to the top surface of thesubstrate; the first etching step of taper-etching the initial supportbody by reactive ion etching using the first etching mask; the step ofremoving the first etching mask; the step of forming a second etchingmask that covers a part of the initial support body except an area wherethe first and second inclined surfaces are to be formed later as viewedin the direction perpendicular to the top surface of the substrate; thesecond etching step of taper-etching the initial support body byreactive ion etching using the second etching mask; and the step ofremoving the second etching mask.

After the second etching step, the first and second inclined surfacesare completed and the initial support body thereby becomes thereflecting film support body. The reflecting film includes a firstportion located on the first inclined surface, and a second portionlocated on the second inclined surface. The first portion includes afirst reflecting surface, and the second portion includes a secondreflecting surface.

In the manufacturing method for the heat-assisted magnetic recordinghead of the present invention, with respect to a virtual plane thatincludes the first inclined surface, the second inclined surface may beoffset in a direction perpendicular to the first inclined surface. Insuch a case, each of the first and second reflecting surfaces has afront end and a rear end. The rear end of the first reflecting surfaceis located farther from the medium facing surface and farther from thetop surface of the substrate than is the front end of the firstreflecting surface. The front end of the second reflecting surface islocated farther from the medium facing surface and farther from the topsurface of the substrate than is the front end of the first reflectingsurface. The rear end of the second reflecting surface is locatedfarther from the medium facing surface and farther from the top surfaceof the substrate than are the rear end of the first reflecting surfaceand the front end of the second reflecting surface. With respect to avirtual plane that includes the first reflecting surface, the secondreflecting surface is offset in a direction perpendicular to the firstreflecting surface.

In the manufacturing method for the heat-assisted magnetic recordinghead of the present invention, each of the first and second reflectingsurfaces may form an angle of 45° with respect to the directionperpendicular to the top surface of the substrate.

In the manufacturing method for the heat-assisted magnetic recordinghead of the present invention, the initial support body may be made ofalumina. The first and second etching steps may use an etching gas thatcontains BCl₃, Cl₂, and one of N₂ and CF₄.

In the manufacturing method for the heat-assisted magnetic recordinghead of the present invention, the first etching step may form aninitial inclined surface in the initial support body, the initialinclined surface being inclined with respect to the directionperpendicular to the top surface of the substrate. The second etchingstep may form the first inclined surface and the second inclinedsurface, the first inclined surface being formed by etching a part ofthe initial support body under the initial inclined surface, the secondinclined surface being formed by etching a part of the initial supportbody not etched in the first etching step. Here, each of the first andsecond etching masks may have a side surface that is closer to themedium facing surface. The side surface of the second etching mask maybe located at a position farther from the medium facing surface by 0.8to 1.2 times an etching depth of the second etching step, than aposition where the side surface of the first etching mask is located.

In the manufacturing method for the heat-assisted magnetic recordinghead of the present invention, the reflecting film may further include acoupling portion that couples the first portion to the second portion.The coupling portion may include a coupling surface that couples thefirst reflecting surface to the second reflecting surface. In this case,an angle formed by the coupling surface with respect to the directionperpendicular to the top surface of the substrate may be greater orsmaller than an angle formed by each of the first and second reflectingsurfaces with respect to the direction perpendicular to the top surfaceof the substrate.

In the manufacturing method for the heat-assisted magnetic recordinghead of the present invention, the reflecting film support body mayinclude a first layer having the first inclined surface and a secondlayer having the second inclined surface. Here, the step of forming theinitial support body may include: the step of forming an initial firstlayer before the step of forming the first etching mask, the initialfirst layer being intended to undergo the formation of the firstinclined surface therein later to thereby become the first layer; andthe step of forming an initial second layer between the step of removingthe first etching mask and the step of forming the second etching mask,the initial second layer being intended to undergo the formation of thesecond inclined surface therein later to thereby become the secondlayer. In such a case, the first etching mask is formed on the initialfirst layer, and the first etching step forms the first inclined surfaceby taper-etching the initial first layer. The second etching mask isformed on the initial second layer, and the second etching step formsthe second inclined surface by taper-etching the initial second layer.

Where the components of the heat-assisted magnetic recording headexcluding the substrate are concerned in the present application, asurface closer to the top surface of the substrate will be defined as“bottom surface,” and a surface farther from the top surface of thesubstrate will be defined as “top surface.”

The internal mirror of the heat-assisted magnetic recording head of thepresent invention includes the reflecting film support body and thereflecting film. The reflecting film support body includes the first andsecond inclined surfaces. With respect to a virtual plane that includesthe first inclined surface, the second inclined surface is offset in adirection perpendicular to the first inclined surface. The reflectingfilm includes the first portion located on the first inclined surfaceand the second portion located on the second inclined surface. The firstportion includes the first reflecting surface, and the second portionincludes the second reflecting surface. With respect to a virtual planethat includes the first reflecting surface, the second reflectingsurface is offset in a direction perpendicular to the first reflectingsurface. The first and second inclined surfaces of the reflecting filmsupport body of the present invention can be formed through a pluralityof steps including two taper-etching operations, for example. The firstand second inclined surfaces can be formed with higher precision,compared with a case of forming a single, plane inclined surface oflarge dimension. Consequently, according to the present invention, thefirst and second reflecting surfaces can also be formed with highprecision. According to the present invention, it is therefore possibleto prevent a drop in use efficiency of the light due to the internalmirror.

In the manufacturing method for the heat-assisted magnetic recordinghead of the present invention, the step of forming the reflecting filmsupport body includes the step of forming the initial support body andthe step of etching the initial support body. The step of etching theinitial support body includes the first and second etching steps oftaper-etching the initial support body. The first and second inclinedsurfaces are completed after the second etching step. According to themanufacturing method of the present invention, the first and secondinclined surfaces can be formed with higher precision, compared with acase of forming a single, plane inclined surface of large dimension.Consequently, according to the present invention, the first and secondreflecting surfaces can also be formed with high precision. According tothe present invention, it is therefore possible to prevent a drop in useefficiency of the light due to the internal mirror.

In the heat-assisted magnetic recording head or the manufacturing methodfor the same of the present invention, the reflecting film has acoupling portion, and the angle formed by the coupling surface of thecoupling portion with respect to the direction perpendicular to the topsurface of the substrate may be smaller than the angle formed by each ofthe first and second reflecting surfaces with respect to the directionperpendicular to the top surface of the substrate. In such a case, it ispossible to prevent part of the light incident on the internal mirrorfrom returning to the light source.

Other and further objects, features and advantages of the presentinvention will appear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the main part of a heat-assistedmagnetic recording head according to a first embodiment of theinvention.

FIG. 2 is a perspective view showing the positional relationship betweenthe laser diode, external mirror, internal mirror, and waveguide of FIG.1, and the direction of polarization of laser light.

FIG. 3 is a perspective view showing the laser diode and the externalmirror of FIG. 1.

FIG. 4 is a perspective view of the heat-assisted magnetic recordinghead according to the first embodiment of the invention.

FIG. 5 is a plan view showing the heat-assisted magnetic recording headas viewed from the direction A of FIG. 4.

FIG. 6 is a cross-sectional view showing a part of the cross section ofthe heat-assisted magnetic recording head taken along line 6-6 of FIG.5.

FIG. 7 is a cross-sectional view showing the configuration of a sliderof the first embodiment of the invention.

FIG. 8 is a front view showing the medium facing surface of the sliderof the first embodiment of the invention.

FIG. 9 is a perspective view showing a near-field light generatingelement and its vicinity in the heat-assisted magnetic recording headaccording to the first embodiment of the invention.

FIG. 10 is a cross-sectional view showing the internal mirror of FIG. 7and its vicinity.

FIG. 11A and FIG. 11B are explanatory diagrams showing a step of amanufacturing method for the heat-assisted magnetic recording headaccording to the first embodiment of the invention.

FIG. 12A and FIG. 12B are explanatory diagrams showing a step thatfollows the step of FIG. 11A and FIG. 11B.

FIG. 13A and FIG. 13B are explanatory diagrams showing a step thatfollows the step of FIG. 12A and FIG. 12B.

FIG. 14A and FIG. 14B are explanatory diagrams showing a step thatfollows the step of FIG. 13A and FIG. 13B.

FIG. 15A and FIG. 15B are explanatory diagrams showing a step thatfollows the step of FIG. 14A and FIG. 14B.

FIG. 16A and FIG. 16B are explanatory diagrams showing a step thatfollows the step of FIG. 15A and FIG. 15B.

FIG. 17A and FIG. 17B are explanatory diagrams showing a step thatfollows the step of FIG. 16A and FIG. 16B.

FIG. 18A and FIG. 18B are explanatory diagrams showing a step thatfollows the step of FIG. 17A and FIG. 17B.

FIG. 19A and FIG. 19B are explanatory diagrams showing a step thatfollows the step of FIG. 18A and FIG. 18B.

FIG. 20A and FIG. 20B are explanatory diagrams showing a step thatfollows the step of FIG. 19A and FIG. 19B.

FIG. 21 is a cross-sectional view showing a step of a series of stepsfor forming the waveguide, the reflecting film support body, and thereflecting film of the first embodiment of the invention.

FIG. 22 is a cross-sectional view showing a step that follows the stepof FIG. 21.

FIG. 23 is a cross-sectional view showing a step that follows the stepof FIG. 22.

FIG. 24 is a cross-sectional view showing a step that follows the stepof FIG. 23.

FIG. 25 is a cross-sectional view showing a step that follows the stepof FIG. 24.

FIG. 26 is a cross-sectional view showing a step that follows the stepof FIG. 25.

FIG. 27 is a cross-sectional view showing a step that follows the stepof FIG. 26.

FIG. 28 is a cross-sectional view showing a step that follows the stepof FIG. 27.

FIG. 29 is a cross-sectional view showing the configuration of aheat-assisted magnetic recording head of a first modification example ofthe first embodiment of the invention.

FIG. 30 is a plan view showing a part of the waveguide and thenear-field light generating element of a heat-assisted magneticrecording head of a second modification example of the first embodimentof the invention.

FIG. 31 is a perspective view of the near-field light generating elementshown in FIG. 30.

FIG. 32 is a cross-sectional view showing an internal mirror and itsvicinity in a heat-assisted magnetic recording head according to asecond embodiment of the invention.

FIG. 33 is an explanatory diagram showing a step of a series of stepsfor forming the waveguide, the reflecting film support body, and thereflecting film of the second embodiment of the invention.

FIG. 34 is a cross-sectional view showing an internal mirror and itsvicinity in a heat-assisted magnetic recording head according to a thirdembodiment of the invention.

FIG. 35 is an explanatory diagram showing a step of a series of stepsfor forming the waveguide, the reflecting film support body, and thereflecting film of the third embodiment of the invention.

FIG. 36 is a cross-sectional view showing a step that follows the stepof FIG. 35.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Preferred embodiments of the present invention will now be described indetail with reference to the drawings. Reference is first made to FIG. 4and FIG. 5 to describe a heat-assisted magnetic recording head and amagnetic disk drive according to a first embodiment of the invention.FIG. 4 is a perspective view of the heat-assisted magnetic recordinghead according to the present embodiment. FIG. 5 is a plan view of theheat-assisted magnetic recording head as viewed from the direction A ofFIG. 4.

The magnetic disk drive of the present embodiment incorporates theheat-assisted magnetic recording head 200 according to the presentembodiment. The heat-assisted magnetic recording head 200 is supportedby a not-shown suspension and is disposed to face acircular-plate-shaped recording medium (magnetic disk) that is driven torotate. In FIG. 4 and FIG. 5, the X direction is a direction across thetracks of the recording medium, the Y direction is a directionperpendicular to the surface of the recording medium, and the Zdirection is the direction of travel of the recording medium as viewedfrom the heat-assisted magnetic recording head 200. The X direction, theY direction and the Z direction are orthogonal to one another.

The heat-assisted magnetic recording head 200 includes a slider 201, anedge-emitting laser diode 202 fixed to the slider 201, and an externalmirror 203 provided outside the slider 201. The slider 201 is nearlyhexahedron-shaped, and has a medium facing surface 201 a that faces therecording medium, a rear surface 201 b opposite to the medium facingsurface 201 a, and four surfaces that couple the medium facing surface201 a to the rear surface 201 b. The medium facing surface 201 a of theslider 201 also functions as the medium facing surface of theheat-assisted magnetic recording head 200. One of the four surfaces thatcouple the medium facing surface 201 a to the rear surface 201 b is atop surface 201 c. The laser diode 202 is fixed to the top surface 201c. The slider 201 has a plurality of terminals 210 provided on the topsurface 201 c. In the present embodiment, the external mirror 203 isfixed to the laser diode 202.

When the recording medium rotates and travels in the Z direction, anairflow passing between the recording medium and the slider 201generates a lift on the upper side in the Y direction of FIG. 4, and thelift is exerted on the slider 201. The lift causes the slider 201 toslightly fly over the surface of the recording medium.

Reference is now made to FIG. 1 and FIG. 7 to FIG. 10 to describe theconfiguration of the slider 201 in detail. FIG. 1 is a perspective viewshowing the main part of the heat-assisted magnetic recording head 200according to the present embodiment. FIG. 7 is a cross-sectional viewshowing the configuration of the slider 201. FIG. 7 shows a crosssection taken along line 7-7 of FIG. 5. FIG. 8 is a front view showingthe medium facing surface 201 a of the slider 201. FIG. 9 is aperspective view showing a near-field light generating element and itsvicinity in the heat-assisted magnetic recording head 200. FIG. 10 is across-sectional view showing an internal mirror and its vicinity in theheat-assisted magnetic recording head 200. The X, Y and Z directionsshown in FIG. 4 are also shown in FIG. 1 and FIG. 7 to FIG. 10. In FIG.7 and FIG. 10, the X direction is orthogonal to the Y and Z directions.In FIG. 8, the Y direction is orthogonal to the X and Z directions.

As shown in FIG. 7 and FIG. 8, the slider 201 includes: a substrate 1made of a ceramic material such as aluminum oxide-titanium carbide(Al₂O₃—TiC) and having a top surface 1 a; an insulating layer 2 made ofan insulating material and disposed on the top surface 1 a of thesubstrate 1; a bottom shield layer 3 made of a magnetic material anddisposed on the insulating layer 2; and an insulating layer 31 made ofan insulating material and disposed around the bottom shield layer 3 onthe insulating layer 2. The insulating layers 2 and 31 are made ofalumina (Al₂O₃), for example. The bottom shield layer 3 and theinsulating layer 31 are flattened at the top.

The slider 201 further includes: a bottom shield gap film 4 which is aninsulating film disposed over the top surfaces of the bottom shieldlayer 3 and the insulating layer 31; a magnetoresistive (MR) element 5as a reproducing element disposed on the bottom shield gap film 4; a topshield gap film 6 which is an insulating film disposed on the MR element5; a top shield layer 7 made of a magnetic material and disposed on thetop shield gap film 6; and an insulating layer 32 made of an insulatingmaterial and disposed around the top shield layer 7 on the top shieldgap film 6. The insulating layer 32 is made of alumina, for example. Thetop shield layer 7 and the insulating layer 32 are flattened at the top.

An end of the MR element 5 is located in the medium facing surface 201a. The MR element 5 may be an element made of a magneto-sensitive filmthat exhibits a magnetoresistive effect, such as an anisotropicmagnetoresistive (AMR) element, a giant magnetoresistive (GMR) element,or a tunneling magnetoresistive (TMR) element. The GMR element may be ofeither the current-in-plane (CIP) type in which a current used fordetecting magnetic signals is fed in a direction nearly parallel to theplane of layers constituting the GMR element or thecurrent-perpendicular-to-plane (CPP) type in which the current used fordetecting magnetic signals is fed in a direction nearly perpendicular tothe plane of layers constituting the GMR element. The parts from thebottom shield layer 3 to the top shield layer 7 constitute a reproducinghead.

The slider 201 further includes: a nonmagnetic layer 8 made of anonmagnetic material and disposed over the top surfaces of the topshield layer 7 and the insulating layer 32; a return magnetic pole layer10 made of a magnetic material and disposed on the nonmagnetic layer 8;and an insulating layer 33 made of an insulating material and disposedaround the return magnetic pole layer 10 on the nonmagnetic layer 8. Thenonmagnetic layer 8 and the insulating layer 33 are made of alumina, forexample. The return magnetic pole layer 10 and the insulating layer 33are flattened at the top.

The slider 201 further includes: an insulating layer 11 disposed on partof the top surfaces of the return magnetic pole layer 10 and theinsulating layer 33; a coil 12 disposed on the insulating layer 11; anda coupling layer 13 disposed on the return magnetic pole layer 10. Thereturn magnetic pole layer 10 and the coupling layer 13 are each made ofa magnetic material. The material of the return magnetic pole layer 10and the coupling layer 13 may be CoFeN, CoNiFe, NiFe or CoFe, forexample. The insulating layer 11 is made of alumina, for example. Thecoil 12 produces a magnetic field corresponding to data to be recordedon the recording medium. The coil 12 is planar spiral-shaped and woundaround the coupling layer 13. The coil 12 is made of a conductivematerial such as copper.

The slider 201 further includes: an insulating layer 14 made of aninsulating material and disposed around the coil 12 and in the spacebetween every adjacent turns of the coil 12; an insulating layer 15disposed around the insulating layer 14 and the coupling layer 13 on theinsulating layer 11; and an insulating layer 16 disposed on the coil 12and the insulating layers 14 and 15. The coil 12, the coupling layer 13and the insulating layers 14 and 15 are flattened at the top. Theinsulating layer 14 is made of photoresist, for example. The insulatinglayers 15 and 16 are made of alumina, for example.

The slider 201 further includes: a bottom yoke layer 17 made of amagnetic material and disposed over the coupling layer 13 and theinsulating layer 16; and a nonmagnetic layer 18 made of a nonmagneticmaterial and disposed around the bottom yoke layer 17 on the insulatinglayer 16. The bottom yoke layer 17 may be made of CoFeN, CoNiFe, NiFe,or CoFe, for example. The nonmagnetic layer 18 is made of alumina, forexample. The bottom yoke layer 17 has an end face that is closer to themedium facing surface 201 a, and this end face is located at a distancefrom the medium facing surface 201 a. The bottom yoke layer 17 and thenonmagnetic layer 18 are flattened at the top.

The slider 201 further includes a magnetic pole 20. The magnetic pole 20includes a first layer 20A and a second layer 20B. The first layer 20Alies over the bottom yoke layer 17 and the nonmagnetic layer 18. Thefirst layer 20A has an end face located in the medium facing surface 201a. This end face is rectangular in shape, for example.

The second layer 20B lies on a part of the first layer 20A near themedium facing surface 201 a. The second layer 20B has a front end facelocated in the medium facing surface 201 a, and a rear end face oppositeto the front end face. The front end face of the second layer 20B isrectangular in shape, for example.

The magnetic pole 20 passes a magnetic flux corresponding to themagnetic field produced by the coil 12, and produces a recordingmagnetic field for recording data on the recording medium by means of aperpendicular magnetic recording system. The position of the end of abit pattern to be recorded on the recording medium depends on theposition of the top edge, i.e., the edge farther from the top surface 1a of the substrate 1, of the front end face of the second layer 20B. Thewidth of the front end face of the second layer 20B taken at the topedge defines the track width.

The width of the end face of the first layer 20A located in the mediumfacing surface 201 a may be equal to or greater than the width of thefront end face of the second layer 20B.

The first layer 20A and the second layer 20B are each made of a magneticmetal material. The material of each of the first layer 20A and thesecond layer 20B may be NiFe, CoNiFe, or CoFe, for example.

The slider 201 further includes a nonmagnetic layer 21 made of anonmagnetic material and disposed around the first layer 20A on thenonmagnetic layer 18. The nonmagnetic layer 21 is made of alumina, forexample. The first layer 20A and the nonmagnetic layer 21 are flattenedat the top.

The slider 201 further includes an internal mirror 30 disposed over thetop surfaces of the first layer 20A and the nonmagnetic layer 21, and awaveguide 26. The internal mirror 30 includes a reflecting film supportbody 27, and a reflecting film 35 supported by the reflecting filmsupport body 27. The reflecting film support body 27 has a groove 27Athat opens in the top surface of the support body 27. The waveguide 26is accommodated in the groove 27A. The reflecting film support body 27also functions as a clad layer for the waveguide 26.

As shown in FIG. 10, the groove 27A of the reflecting film support body27 has a bottom 271, a first inclined surface 272 a, a second inclinedsurface 272 b, and a coupling surface 272 c that couples the inclinedsurfaces 272 a and 272 b to each other. Each of the inclined surfaces272 a and 272 b and the coupling surface 272 c is a plane surface. Theinclined surface 272 a has a front end 272 a 1 that is closer to themedium facing surface 201 a, and a rear end 272 a 2 that is farther fromthe medium facing surface 201 a. The inclined surface 272 b has a frontend 272 b 1 that is closer to the medium facing surface 201 a, and arear end 272 b 2 that is farther from the medium facing surface 201 a.The rear end 272 a 2 of the inclined surface 272 a is located fartherfrom the medium facing surface 201 a and farther from the top surface 1a of the substrate 1 than is the front end 272 a 1 of the inclinedsurface 272 a. The front end 272 b 1 of the inclined surface 272 b islocated farther from the medium facing surface 201 a and farther fromthe top surface 1 a of the substrate 1 than is the front end 272 a 1 ofthe inclined surface 272 a. The rear end 272 b 2 of the inclined surface272 b is located farther from the medium facing surface 201 a andfarther from the top surface 1 a of the substrate 1 than are the rearend 272 a 2 of the inclined surface 272 a and the front end 272 b 1 ofthe inclined surface 272 b.

The inclined surfaces 272 a and 272 b are arranged so as not to overlapeach other as viewed in a direction perpendicular to the top surface 1 aof the substrate 1. The inclined surface 272 a is connected to thebottom 271. With respect to a virtual plane that includes the inclinedsurface 272 a, the inclined surface 272 b is offset in a directionperpendicular to the inclined surface 272 a. Each of the inclinedsurfaces 272 a and 272 b forms an angle of, for example, 45° withrespect to the direction perpendicular to the top surface 1 a of thesubstrate 1. With respect to the direction perpendicular to the topsurface 1 a of the substrate 1, the coupling surface 272 c forms anangle greater than that formed by each of the inclined surfaces 272 aand 272 b.

The reflecting film 35 is a film of metal such as Al, Ag, or Au, with athickness of 50 to 200 nm or so. As shown in FIG. 10, the reflectingfilm 35 includes: a first portion 351 located on the first inclinedsurface 272 a; a second portion 352 located on the second inclinedsurface 272 b; a coupling portion 353 located on the coupling surface272 c and coupling the first portion 351 to the second portion 352; anda portion 354 located on the bottom 271 and coupled to the first portion351. It should be noted that the reflecting film 35 need not include theportion 354.

The first portion 351 includes a first reflecting surface 351 a, whichis the surface opposite to that in contact with the inclined surface 272a. The second portion 352 includes a second reflecting surface 352 a,which is the surface opposite to that in contact with the inclinedsurface 272 b. The coupling portion 353 includes a coupling surface 353a that couples the first reflecting surface 351 a to the secondreflecting surface 352 a. Each of the reflecting surfaces 351 a and 352a and the coupling surface 353 a is a plane surface. The firstreflecting surface 351 a has a front end 351 a 1 that is closer to themedium facing surface 201 a, and a rear end 351 a 2 that is farther fromthe medium facing surface 201 a. The second reflecting surface 352 a hasa front end 352 a 1 that is closer to the medium facing surface 201 a,and a rear end 352 a 2 that is farther from the medium facing surface201 a.

The rear end 351 a 2 of the first reflecting surface 351 a is locatedfarther from the medium facing surface 201 a and farther from the topsurface 1 a of the substrate 1 than is the front end 351 a 1 of thefirst reflecting surface 351 a. The front end 352 a 1 of the secondreflecting surface 352 a is located farther from the medium facingsurface 201 a and farther from the top surface 1 a of the substrate 1than is the front end 351 a 1 of the first reflecting surface 351 a. Therear end 352 a 2 of the second reflecting surface 352 a is locatedfarther from the medium facing surface 201 a and farther from the topsurface 1 a of the substrate 1 than are the rear end 351 a 2 of thefirst reflecting surface 351 a and the front end 352 a 1 of the secondreflecting surface 352 a.

With respect to a virtual plane that includes the first reflectingsurface 351 a, the second reflecting surface 352 a is offset in adirection perpendicular to the first reflecting surface 351 a. Each ofthe reflecting surfaces 351 a and 352 a forms an angle of, for example,45° with respect to the direction perpendicular to the top surface 1 aof the substrate 1. With respect to the direction perpendicular to thetop surface 1 a of the substrate 1, the coupling surface 353 a forms anangle greater than that formed by each of the reflecting surfaces 351 aand 352 a. The reflecting surfaces 351 a and 352 a reflect light that isemitted from a light source disposed above the waveguide 26 so that thereflected light travels through the waveguide 26 toward the mediumfacing surface 201 a.

The waveguide 26 is made of a dielectric material that transmits laserlight to be described later. The reflecting film support body 27 is madeof a dielectric material that has a refractive index lower than that ofthe waveguide 26. For example, the waveguide 26 can be made of Ta₂O₅which has a refractive index of approximately 2.1, and the reflectingfilm support body 27 can be made of alumina which has a refractive indexof approximately 1.8. The second layer 20B, the waveguide 26, and thereflecting film support body 27 are flattened at the top. The shape ofthe waveguide 26 will be described in detail later.

The slider 201 further includes an interposition layer 25 disposed overthe top surfaces of the second layer 20B, the waveguide 26 and thereflecting film support body 27. The interposition layer 25 is made of adielectric material that has a refractive index lower than that of thewaveguide 26 and transmits the laser light. For example, theinterposition layer 25 can be made of alumina which has a refractiveindex of approximately 1.8. The interposition layer 25 has a thicknesswithin the range of 30 to 70 nm, for example.

The slider 201 further includes: a near-field light generating element23 disposed on the interposition layer 25; a clad layer 24 disposedaround the near-field light generating element 23 on the interpositionlayer 25; and a clad layer 29 having a top surface 29 a and disposedover the near-field light generating element 23 and the clad layer 24.The near-field light generating element 23 and the clad layer 24 areflattened at the top. The near-field light generating element 23 is madeof metal. Specifically, the near-field light generating element 23 ismade of one of Au, Ag, Al, Cu, Pd, Pt, Rh and Ir, or of an alloycomposed of two or more of these elements. The clad layers 24 and 29 areeach made of a dielectric material that has a refractive index lowerthan that of the waveguide 26 and transmits the laser light. Forexample, the clad layers 24 and 29 can be made of alumina which has arefractive index of approximately 1.8. The clad layer 29 has a thicknesswithin the range of 0.1 to 0.5 μm, for example. The top surface 29 a ofthe clad layer 29 constitutes the top surface 201 c of the slider 201.The substrate 1 has the top surface 1 a facing toward the magnetic pole20, the near-field light generating element 23 and the waveguide 26. Thetop surface 201 c of the slider 201 lies at an end above the top surface1 a of the substrate 1.

As shown in FIG. 9, the near-field light generating element 23 has anear-field light generating part 23 g located in the medium facingsurface 201 a. The near-field light generating element 23 is in theshape of a triangular prism, having an outer surface described below.The outer surface of the near-field light generating element 23includes: a first end face 23 a that is located in the medium facingsurface 201 a; a second end face 23 b that is farther from the mediumfacing surface 201 a; and a coupling part that couples the first endface 23 a to the second end face 23 b. The coupling part includes: a topsurface 23 c that is farther from the top surface 1 a of the substrate1; two side surfaces 23 d and 23 e that decrease in distance from eachother with decreasing distance to the top surface 1 a of the substrate1; and an edge part 23 f that connects the two side surfaces 23 d and 23e to each other. The first end face 23 a is shaped like an isoscelestriangle with the vertex downward. The first end face 23 a includes thenear-field light generating part 23 g. Specifically, the near-fieldlight generating part 23 g refers to the end of the edge part 23 f andits vicinity in the end face 23 a.

As shown in FIG. 9, the length of the near-field light generatingelement 23 in the direction perpendicular to the medium facing surface201 a will be denoted by the symbol H_(PA); the width of the first endface 23 a at its top edge will be denoted by the symbol W_(PA); and thelength of the first end face 23 a in the direction perpendicular to thetop surface 1 a of the substrate 1 will be denoted by the symbol T_(PA).The length H_(PA) of the near-field light generating element 23 in thedirection perpendicular to the medium facing surface 201 a is greaterthan the length T_(PA) of the first end face 23 a in the directionperpendicular to the top surface 1 a of the substrate 1. Both of W_(PA)and T_(PA) are smaller than or equal to the wavelength of light thatpropagates through the waveguide 26. W_(PA) falls within the range of 50to 150 nm, for example. T_(PA) falls within the range of 50 to 150 nm,for example. H_(PA) falls within the range of 0.25 to 2.5 μm, forexample.

A detailed description will now be given of the waveguide 26 withreference to FIG. 1, FIG. 5, FIG. 7, FIG. 9 and FIG. 10. As shown inFIG. 1, FIG. 5 and FIG. 7, the waveguide 26 extends in the directionperpendicular to the medium facing surface 201 a (the Y direction). Thewaveguide 26 has an outer surface. The outer surface includes: a frontend face 26 a that is closer to the medium facing surface 201 a; a rearend face 26 b that is farther from the medium facing surface 201 a; atop surface 26 c that is farther from the top surface 1 a of thesubstrate 1; a bottom surface 26 d that is closer to the top surface 1 aof the substrate 1; and two side surfaces 26 e and 26 f that are locatedon opposite sides in the track width direction. The front end face 26 ais opposed to the rear end face of the second layer 20B with a part ofthe reflecting film support body 27 interposed therebetween.

As shown in FIG. 9, the outer surface of the waveguide 26 includes anopposed portion 26 g that is opposed to a part of the coupling part ofthe outer surface of the near-field light generating element 23. In thepresent embodiment, in particular, the opposed portion 26 g is a portionof the top surface 26 c of the waveguide 26 that is opposed to a part ofthe edge part 23 f of the near-field light generating element 23 and itsvicinity with the interposition layer 25 interposed therebetween. Thepreviously-mentioned configuration that the length H_(PA) of thenear-field light generating element 23 in the direction perpendicular tothe medium facing surface 201 a is greater than the length T_(PA) of thefirst end face 23 a in the direction perpendicular to the top surface 1a of the substrate 1 is necessary in order that the opposed portion 26g, which is a part of the top surface 26 c of the waveguide 26, isopposed to a part of the edge part 23 f of the near-field lightgenerating element 23 and its vicinity with the interposition layer 25interposed therebetween.

As shown in FIG. 10, the rear end face 26 b is in contact with thereflecting surfaces 351 a and 352 a and the coupling surface 353 a. Thedistance between the medium facing surface 201 a and an arbitrary pointon the rear end face 26 b increases with increasing distance between thearbitrary point and the top surface 1 a of the substrate 1.

As shown in FIG. 7 and FIG. 10, the internal mirror 30 reflects lightthat is emitted from the light source disposed above the waveguide 26with its reflecting surfaces 351 a and 352 a, so that the reflectedlight travels through the waveguide 26 toward the medium facing surface201 a. More specifically, the internal mirror 30 is configured toreflect the light that comes from above the waveguide 26, enters thewaveguide 26 from the top surface 26 c of the waveguide 26 and reachesthe rear end face 26 b and the reflecting surfaces 351 a and 352 a, sothat the reflected light travels toward the front end face 26 a.

Reference is now made to FIG. 3 to describe the laser diode 202 and theexternal mirror 203. FIG. 3 is a perspective view showing the laserdiode 202 and the external mirror 203. As shown in FIG. 3, the laserdiode 202 includes: an n-substrate 211 having a top surface and a bottomsurface; a laser structure part 212 disposed below the bottom surface ofthe n-substrate 211; an n-electrode 213 joined to the top surface of then-substrate 211; and a p-electrode 214 joined to the laser structurepart 212 such that the laser structure part 212 is sandwiched betweenthe n-substrate 211 and the p-electrode 214. The laser structure part212 includes at least an n-clad layer 221, an active layer 222 and ap-clad layer 223. The n-clad layer 221 is disposed between then-substrate 211 and the active layer 222. The p-clad layer 223 isdisposed between the p-electrode 214 and the active layer 222. Theactive layer 222 has a surface that faces the n-clad layer 221, and asurface that faces the p-clad layer 223.

The laser diode 202 is rectangular-solid-shaped and has a bottom surface202 a and a top surface 202 b lying at opposite ends in a directionperpendicular to the plane of the active layer 222, and four surfacesthat connect the bottom surface 202 a and the top surface 202 b to eachother. The bottom surface 202 a and the top surface 202 b are parallelto the plane of the active layer 222. The bottom surface 202 a is formedby the surface of the p-electrode 214. The top surface 202 b is formedby the surface of the n-electrode 213. One of the four surfaces thatconnect the bottom surface 202 a and the top surface 202 b to each otheris a surface 202 c. The surface 202 c includes an emission part 222 afor emitting laser light. The emission part 222 a lies at an end of theactive layer 222. Hereinafter, the surface 202 c will be referred to asthe emitting end face. The bottom surface 202 a and the top surface 202b each have an area greater than that of the emitting end face 202 c.

The laser diode 202 is fixed to the slider 201 such that the bottomsurface 202 a lying at an end in the direction perpendicular to theplane of the active layer 222 faces the top surface 201 c of the slider201. In the present embodiment, in particular, the bottom surface 202 aof the laser diode 202 is joined to the top surface 201 c of the slider201. For example, an adhesive is used to join the bottom surface 202 aof the laser diode 202 to the top surface 201 c of the slider 201.

The slider 201 may include a conductor layer that is arranged to beexposed in the top surface 201 c and connects the p-electrode 214 of thelaser diode 202 to one of the terminals 210. Here, the p-electrode 214may be electrically connected to the conductor layer by joining thebottom surface 202 a of the laser diode 202 to the top surface 201 c ofthe slider 201. In such a case, the bottom surface 202 a of the laserdiode 202 and the conductor layer are connected to each other bysoldering, for example. The n-electrode 213 of the laser diode 202 isconnected to another one of the terminals 210 with a bonding wire, forexample.

In the present embodiment, as shown in FIG. 3 and FIG. 6, the distanceD1 between the bottom surface 202 a and the emission part 222 a of thelaser diode 202 is smaller than the distance D2 between the top surface202 b and the emission part 222 a of the laser diode 202.

The external mirror 203 includes a reflecting part 203 a and to-be-fixedparts 203 b and 203 c each of which is shaped like a plate. Theto-be-fixed parts 203 b and 203 c are coupled to each other to form anangle of 90° therebetween. The reflecting part 203 a is coupled to anend of the to-be-fixed part 203 c so as to form an angle of 135° withrespect to the to-be-fixed part 203 c. The to-be-fixed part 203 b iscoupled to the opposite end of the to-be-fixed part 203 c. Theto-be-fixed part 203 b is fixed to the top surface 202 a while theto-be-fixed part 203 c is fixed to the emitting end face 202 c, wherebythe external mirror 203 is fixed to the laser diode 202. The reflectingpart 203 a is located in front of the emission part 222 a. One of thesurfaces of the reflecting part 203 a that is closer to the emissionpart 222 a constitutes a reflecting surface for reflecting the laserlight emitted from the emission part 222 a toward the waveguide 26 inthe slider 201. The normal to the reflecting surface forms an angle of45° with respect to the direction of travel of the laser light emittedfrom the emission part 222 a.

The external mirror 203 can be formed by, for example, molding a bodyout of an insulating material such as resin or glass, and forming ametal film on at least a part of the body that is to make the reflectingsurface by vapor deposition, sputtering, or the like.

The portion from the return magnetic pole layer 10 to the clad layer 29,and the laser diode 202 and the external mirror 203 constitute arecording head.

Reference is now made to FIG. 1, FIG. 2, FIG. 6 and FIG. 7 to describethe path of the laser light emitted from the emission part 222 a of thelaser diode 202. FIG. 2 is a perspective view showing the positionalrelationship between the laser diode 202, the external mirror 203, theinternal mirror 30, and the waveguide 26 of FIG. 1, and the direction ofpolarization of the laser light. FIG. 6 is a cross-sectional viewshowing a part of the cross section of the heat-assisted magneticrecording head 200 taken along line 6-6 of FIG. 5. The X, Y and Zdirections shown in FIG. 4 are also shown in FIG. 2 and FIG. 6. In FIG.6, the Y direction is orthogonal to the X and Z directions.

The laser light emitted from the emission part 222 a of the laser diode202 is reflected by the reflecting surface of the reflecting part 203 aof the external mirror 203, passes through the clad layer 29, the cladlayer 24, and the interposition layer 25, and enters the waveguide 26from the top surface 26 c to reach the rear end face 26 b and thereflecting surfaces 351 a and 352 a. The laser light is then reflectedby the reflecting surfaces 351 a and 352 a of the reflecting film 35 ofthe internal mirror 30 so as to travel through the waveguide 26 towardthe medium facing surface 201 a (the front end face 26 a).

As shown in FIG. 1 and FIG. 2, the laser light emitted from the emissionpart 222 a will be designated by the reference symbol L1; the laserlight reflected by the external mirror 203 will be designated by thereference symbol L2; and the laser light reflected by the internalmirror 30 will be designated by the reference symbol L3. In the presentembodiment, the laser diode 202, the external mirror 203, the internalmirror 30 and the waveguide 26 are arranged so that the direction oftravel of the laser light L1 emitted from the emission part 222 a andthe direction of travel of the laser light L3 reflected by the internalmirror 30 are orthogonal to each other as viewed from above the topsurface 201 c of the slider 201.

FIG. 1 and FIG. 2 show an example of the configuration of the waveguide26. In this example, the two side surfaces 26 e and 26 f of thewaveguide 26 are formed as a reflecting surface of parabolic shape inthe vicinity of the front end face 26 a as viewed from above. Thisreflecting surface has the function of collecting the light propagatingthrough the waveguide 26 to the vicinity of the front end face 26 a.

With reference to FIG. 2, the direction of polarization of the laserlight in the present embodiment will be described. In the presentembodiment, the laser diode 202 emits linearly polarized laser lightwhose electric field oscillates in a direction parallel to the plane ofthe active layer 222, i.e., laser light of TE mode, from the emissionpart 222 a. The direction of oscillation of the electric field of thelaser light emitted from the emission part 222 a is parallel to the XYplane. The laser light emitted from the emission part 222 a is reflectedby the reflecting surface of the reflecting part 203 a of the externalmirror 203 and travels toward the waveguide 26. Here, the direction ofoscillation of the electric field of this laser light is parallel to theYZ plane. This laser light passes through the clad layer 29, the cladlayer 24, and the interposition layer 25, enters the waveguide 26 fromthe top surface 26 c, and is reflected by the internal mirror 30. Thedirection of oscillation of the electric field of the laser lightreflected by the internal mirror 30 is parallel to the YZ plane. Thelaser light reflected by the internal mirror 30 propagates through thewaveguide 26 to reach the opposed portion 26 g. The direction ofoscillation of the electric field of this laser light is perpendicularto the opposed portion 26 g. This makes it possible to produce surfaceplasmons of high intensity on the near-field light generating element23.

As has been described, the heat-assisted magnetic recording head 200according to the present embodiment includes the slider 201, theedge-emitting laser diode 202 fixed to the slider 201, and the externalmirror 203 provided outside the slider 201. The slider 201 includes: themedium facing surface 201 a that faces the recording medium; thereproducing head; and a portion of the recording head excluding thelaser diode 202 and the external mirror 203 (hereinafter, referred to asan in-slider portion of the recording head). The reproducing head andthe in-slider portion of the recording head are stacked on the substrate1. Relative to the reproducing head, the in-slider portion of therecording head is located on the front side (trailing side) in thedirection of travel of the recording medium (the Z direction).

The reproducing head includes: the MR element 5 as the reproducingelement; the bottom shield layer 3 and the top shield layer 7 forshielding the MR element 5, the respective portions of the bottom shieldlayer 3 and the top shield layer 7 located near the medium facingsurface 201 a being opposed to each other with the MR element 5therebetween; the bottom shield gap film 4 disposed between the MRelement 5 and the bottom shield layer 3; and the top shield gap film 6disposed between the MR element 5 and the top shield layer 7.

The in-slider portion of the recording head includes the return magneticpole layer 10, the coil 12, the coupling layer 13, the bottom yoke layer17, and the magnetic pole 20. The coil 12 produces a magnetic fieldcorresponding to data to be recorded on the recording medium. The returnmagnetic pole layer 10, the coupling layer 13, the bottom yoke layer 17and the magnetic pole 20 form a magnetic path for passing a magneticflux corresponding to the magnetic field produced by the coil 12. Themagnetic pole 20 includes the first layer 20A and the second layer 20B.The magnetic pole 20 allows the magnetic flux corresponding to themagnetic field produced by the coil 12 to pass, and produces a recordingmagnetic field for recording data on the recording medium by means ofthe perpendicular magnetic recording system. The position of the end ofa bit pattern to be recorded on the recording medium depends on theposition of the top edge, i.e., the edge farther from the top surface 1a of the substrate 1, of the front end face of the second layer 20Blocated in the medium facing surface 201 a. The width of the front endface of the second layer 20B located in the medium facing surface 201 ataken at the top edge defines the track width. The return magnetic polelayer 10, the coupling layer 13 and the bottom yoke layer 17 have thefunction of returning, to the magnetic pole 20, a magnetic flux that hasbeen generated from the magnetic pole 20 and has magnetized therecording medium.

The in-slider portion of the recording head further includes thenear-field light generating element 23, the interposition layer 25, thewaveguide 26, the clad layers 24 and 29, and the internal mirror 30. Thesubstrate 1 has the top surface 1 a. The magnetic pole 20, the waveguide26, the near-field light generating element 23, and the internal mirror30 are located above the top surface 1 a of the substrate 1. Thewaveguide 26, the near-field light generating element 23, and theinternal mirror 30 are located farther from the top surface 1 a of thesubstrate 1 than is the first layer 20A of the magnetic pole 20. Thefront end face 26 a of the waveguide 26 is opposed to the rear end faceof the second layer 20B. The rear end face 26 b of the waveguide 26 isin contact with the reflecting surfaces 351 a and 352 a of thereflecting film 35 of the internal mirror 30. The near-field lightgenerating element 23 is located farther from the top surface 1 a of thesubstrate 1 than is the second layer 20B. The interposition layer 25,the near-field light generating element 23, and the clad layers 24 and29 are located farther from the top surface 1 a of the substrate 1 thanis the waveguide 26. The clad layer 29 has the top surface 29 a. The topsurface 29 a of the clad layer 29 constitutes the top surface 201 c ofthe slider 201.

The outer surface of the near-field light generating element 23includes: the first end face 23 a that is located in the medium facingsurface 201 a; the second end face 23 b that is farther from the mediumfacing surface 201 a; and the coupling part that couples the first endface 23 a to the second end face 23 b. The coupling part includes: thetop surface 23 c that is farther from the top surface 1 a of thesubstrate 1; the two side surfaces 23 d and 23 e that decrease indistance from each other with decreasing distance to the top surface 1 aof the substrate 1; and the edge part 23 f that connects the two sidesurfaces 23 d and 23 e to each other. The first end face 23 a includesthe near-field light generating part 23 g. The length H_(PA) of thenear-field light generating element 23 in the direction perpendicular tothe medium facing surface 201 a (the Y direction) is greater than thelength T_(PA) of the first end face 23 a in the direction perpendicularto the top surface 1 a of the substrate 1. As will be detailed later,surface plasmons are excited on the near-field light generating element23 based on the light propagating through the waveguide 26. The surfaceplasmons propagate to the near-field light generating part 23 g, and thenear-field light generating part 23 g generates near-field light basedon the surface plasmons.

The waveguide 26 is located closer to the top surface 1 a of thesubstrate 1 than is the near-field light generating element 23. Theouter surface of the waveguide 26 includes the opposed portion 26 g thatis opposed to a part of the edge part 23 f of the near-field lightgenerating element 23 with the interposition layer 25 interposedtherebetween.

The reflecting film support body 27, the interposition layer 25, and theclad layers 24 and 29 are each made of a dielectric material having arefractive index lower than that of the waveguide 26. Consequently, theouter surface of the waveguide 26 excluding the portion in contact withthe reflecting film 35 is covered with the dielectric material that islower in refractive index than the waveguide 26.

The recording head further includes the edge-emitting laser diode 202fixed to the slider 201, and the external mirror 203 fixed to the laserdiode 202. The laser diode 202 includes: the active layer 222; theemitting end face 202 c that lies at an end in the direction parallel tothe plane of the active layer 222 and includes the emission part 222 afor emitting laser light; and the bottom surface 202 a that lies at anend in the direction perpendicular to the plane of the active layer 222.The laser diode 202 is arranged so that the bottom surface 202 a facesthe top surface 201 c of the slider 201. The external mirror 203reflects the laser light emitted from the emission part 222 a toward thewaveguide 26. The laser light reflected by the external mirror 203passes through the clad layer 29, the clad layer 24, and theinterposition layer 25, and enters the waveguide 26 from the top surface26 e to reach the rear end face 26 b, where the laser light is reflectedby the internal mirror 30 so as to travel through the waveguide 26toward the medium facing surface 201 a (the front end face 26 a).

Now, the principle of generation of near-field light in the presentembodiment and the principle of heat-assisted magnetic recording usingthe near-field light will be described in detail. As described above,the laser light emitted from the emission part 222 a of the laser diode202 is reflected by the external mirror 203, passes through the cladlayer 29, the clad layer 24 and the interposition layer 25, enters thewaveguide 26 from the top surface 26 c, and reaches the rear end face 26b. The laser light is then reflected by the internal mirror 30 andtravels through the waveguide 26 toward the medium facing surface 201 a(the front end face 26 a). Propagating through the waveguide 26, thelaser light reaches the vicinity of the opposed portion 26 g. The laserlight is then totally reflected at the interface between the opposedportion 26 g and the interposition layer 25, and this generatesevanescent light permeating into the interposition layer 25. As aresult, the evanescent light and the collective oscillations of chargeson a part of the coupling part (a part of the edge part 23 f and itsvicinity) of the outer surface of the near-field light generatingelement 23, i.e., surface plasmons, are coupled with each other toexcite a system of surface plasmon polaritons. In this way, surfaceplasmons are excited on the near-field light generating element 23.

The surface plasmons excited on the near-field light generating element23 propagate along the edge part 23 f of the near-field light generatingelement 23 toward the near-field light generating part 23 g.Consequently, the surface plasmons concentrate at the near-field lightgenerating part 23 g, and the near-field light generating part 23 ggenerates near-field light based on the surface plasmons. The near-fieldlight is projected toward the recording medium, reaches the surface ofthe recording medium and heats a part of the magnetic recording layer ofthe recording medium. This lowers the coercivity of the part of themagnetic recording layer. In heat-assisted magnetic recording, the partof the magnetic recording layer with the lowered coercivity is subjectedto a recording magnetic field produced by the magnetic pole 20 for datarecording.

Reference is now made to FIG. 11A to FIG. 20A and FIG. 11B to FIG. 20Bto describe a manufacturing method for the heat-assisted magneticrecording head 200 according to the present embodiment. FIG. 11A to FIG.20A each show a cross section of a stack of layers in the process ofmanufacturing the heat-assisted magnetic recording head 200, the crosssection being perpendicular to the medium facing surface 201 a and thetop surface 1 a of the substrate 1. In FIG. 11A to FIG. 20A, the symbol“ABS” indicates the position where the medium facing surface 201 a is tobe formed. FIG. 11B to FIG. 20B show cross sections at the position ABSof FIG. 11A to FIG. 20A, respectively.

In the manufacturing method for the heat-assisted magnetic recordinghead 200 according to the present embodiment, first, the insulatinglayer 2 is formed on the substrate 1 as shown in FIG. 11A and FIG. 11B.Next, the bottom shield layer 3 is formed on the insulating layer 2.Next, the insulating layer 31 is formed to cover the bottom shield layer3. The insulating layer 31 is then polished by, for example, chemicalmechanical polishing (hereinafter referred to as CMP), until the bottomshield layer 3 is exposed. This flattens the bottom shield layer 3 andthe insulating layer 31 at the top. Next, the bottom shield gap film 4is formed over the bottom shield layer 3 and the insulating layer 31.Next, the MR element 5 and not-shown leads connected to the MR element 5are formed on the bottom shield gap film 4. Next, the top shield gapfilm 6 is formed to cover the MR element 5 and the leads. Next, the topshield layer 7 is formed on the top shield gap film 6. Next, theinsulating layer 32 is formed to cover the top shield layer 7. Next, theinsulating layer 32 is polished by, for example, CMP, until the topshield layer 7 is exposed. This flattens the top shield layer 7 and theinsulating layer 32 at the top. Next, the nonmagnetic layer 8 is formedover the top shield layer 7 and the insulating layer 32. Next, thereturn magnetic pole layer 10 is formed on the nonmagnetic layer 8.Next, the insulating layer 33 is formed to cover the return magneticpole layer 10. The insulating layer 33 is then polished by, for example,CMP, until the return magnetic pole layer 10 is exposed. This flattensthe return magnetic pole layer 10 and the insulating layer 33 at thetop. Next, the insulating layer 11 is formed on part of the top surfacesof the return magnetic pole layer 10 and the insulating layer 33.

FIG. 12A and FIG. 12B show the next step. In this step, first, the coil12 is formed on the insulating layer 11 by frame plating, for example.Next, the coupling layer 13 is formed on the return magnetic pole layer10 by frame plating, for example. Alternatively, the coil 12 may beformed after forming the coupling layer 13. Next, the insulating layer14 made of photoresist, for example, is selectively formed around thecoil 12 and in the space between every adjacent turns of the coil 12.Next, the insulating layer 15 is formed over the entire top surface ofthe stack by sputtering, for example. The insulating layer 15 is thenpolished by, for example, CMP, until the coil 12 and the coupling layer13 are exposed. This flattens the coil 12, the coupling layer 13 and theinsulating layers 14 and 15 at the top.

FIG. 13A and FIG. 13B show the next step. In this step, first, theinsulating layer 16 is formed. Next, the bottom yoke layer 17 is formedover the coupling layer 13 and the insulating layer 16 by frame plating,for example. Next, the nonmagnetic layer 18 is formed over the entiretop surface of the stack. The nonmagnetic layer 18 is then polished by,for example, CMP, until the bottom yoke layer 17 is exposed. Thisflattens the bottom yoke layer 17 and the nonmagnetic layer 18 at thetop.

FIG. 14A and FIG. 14B show the next step. In this step, first, the firstlayer 20A is formed over the bottom yoke layer 17 and the nonmagneticlayer 18 by frame plating, for example. Next, the nonmagnetic layer 21is formed over the entire top surface of the stack. The nonmagneticlayer 21 is then polished by, for example, CMP, until the first layer20A is exposed. This flattens the first layer 20A and the nonmagneticlayer 21 at the top.

FIG. 15A and FIG. 15B show the next step. In this step, the second layer20B is formed on the first layer 20A by frame plating, for example.

FIG. 16A and FIG. 16B show the next step. In this step, first, aninitial support body 27P is formed over the entire top surface of thestack. The initial support body 27 is intended to undergo the formationof the groove 27A therein later to thereby become the reflecting filmsupport body 27. The groove 27A has the inclined surfaces 272 a and 272b. Next, the initial support body 27P is polished by, for example, CMP,until the second layer 20B is exposed. This flattens the second layer20B and the initial support body 27P at the top.

FIG. 17A and FIG. 17B show the next step. In this step, first, thegroove 27A is formed in the initial support body 27P by selectivelyetching the initial support body 27P by reactive ion etching(hereinafter referred to as RIE). This makes the initial support body27P into the reflecting film support body 27. Next, a metal film 35P,which is to become the reflecting film 35 later, is formed over at leastthe inclined surfaces 272 a and 272 b and the coupling surface 272 c ofthe surface of the groove 27A of the reflecting film support body 27.

FIG. 18A and FIG. 18B show the next step. In this step, first, adielectric layer that is to become the waveguide 26 later is formed overthe entire top surface of the stack. Next, the dielectric layer and themetal film 35P are polished by, for example, CMP, until the second layer20B and the reflecting film support body 27 are exposed. This flattensthe second layer 20B, the reflecting film support body 27 and thedielectric layer at the top. As a result, the dielectric layer left inthe groove 27A of the reflecting film support body 27 makes thewaveguide 26. The metal film 35P left in the groove 27A of thereflecting film support body 27 makes the reflecting film 35. The seriesof steps for forming the waveguide 26, the reflecting film support body27 and the reflecting film 35 will be described in more detail later.

FIG. 19A and FIG. 19B show the next step. In this step, first, theinterposition layer 25 is formed over the second layer 20B, thewaveguide 26 and the reflecting film support body 27. Next, the cladlayer 24 is formed on the interposition layer 25. The clad layer 24 isthen selectively etched to form therein a groove for accommodating thenear-field light generating element 23. Next, the near-field lightgenerating element 23 is formed to be accommodated in the groove of theclad layer 24. Next, the clad layer 29 is formed over the entire topsurface of the stack. Wiring, the terminals 210, and other componentsare then formed on the top surface 29 a of the clad layer 29.

Next, as shown in FIG. 20A and FIG. 20B, the laser diode 202 with theexternal mirror 203 fixed thereto is fixed to the top surface 29 a ofthe clad layer 29, i.e., the top surface 201 c of the slider 201.

Next, the substrate is cut into sliders, and polishing of the mediumfacing surface 201 a, fabrication of flying rails, etc. are performed tothereby complete the heat-assisted magnetic recording head.

Now, the series of steps for forming the waveguide 26, the reflectingfilm support body 27 and the reflecting film 35 will be described inmore detail with reference to FIG. 10 and FIG. 21 to FIG. 28. FIG. 21 toFIG. 28 each show a cross section of a part of a stack of layers in theprocess of manufacturing the heat-assisted magnetic recording head, thecross section being perpendicular to the medium facing surface 201 a andthe top surface 1 a of the substrate 1. In FIG. 21 to FIG. 25, theportions lying closer to the substrate 1 than the initial support body27P are omitted. In FIG. 26 to FIG. 28, the portions lying closer to thesubstrate 1 than the reflecting film support body 27 are omitted.

FIG. 21 shows the step after the second layer 20B and the initialsupport body 27P shown in FIG. 16A and FIG. 16B are flattened at thetop. In this step, a first etching mask 41 is formed on the top surfaceof the initial support body 27P. The etching mask 41 is formed bypatterning a photoresist layer by photolithography, for example. Theetching mask 41 has an opening that has a shape corresponding to theplanar shape of the waveguide 26. The etching mask 41 covers a part ofthe initial support body 27P except the area where the first inclinedsurface 272 a is to be formed later as viewed in the directionperpendicular to the top surface 1 a of the substrate 1. In FIG. 21, theetching mask 41 has a side surface 41 a that is closer to the positionwhere the medium facing surface 201 a is to be formed. A metal mask thathas an opening having a shape corresponding to the planar shape of thewaveguide 26 may be formed between the initial support body 27P and theetching mask 41. The metal mask may be made of Ta, for example.

FIG. 22 shows the next step. In this step, the initial support body 27Pis taper-etched by RIE using the etching mask 41. This step will bereferred to as a first etching step.

As shown in FIG. 22, the taper-etching of the initial support body 27Pforms an initial groove 27AP in the initial support body 27P. Theinitial groove 27AP has an initial bottom 271P, an initial inclinedsurface 272P, and not-shown initial sidewalls. The initial inclinedsurface 272P is inclined with respect to the direction perpendicular tothe top surface 1 a of the substrate 1. Suppose, for example, that theinitial support body 27P is made of alumina (Al₂O₃). In this case, inthe first etching step, the initial support body 27P is taper-etched byRIE using an etching gas that contains BCl₃, Cl₂, and one of CF₄ and N₂.BCl₃ and Cl₂ are the main components that contribute to the etching ofthe initial support body 27P. CF₄ and N₂ are gases for forming asidewall-protecting film on the sidewalls of the etched groove while theetching of the initial support body 27P is in process. Since the etchinggas contains CF₄ or N₂, a sidewall-protecting film is formed on thesidewalls of the groove during the etching of the initial support body27P. This makes the initial inclined surface 272P inclined with respectto the direction perpendicular to the top surface 1 a of the substrate1. Note that the not-shown initial sidewalls are also inclined withrespect to the direction perpendicular to the top surface 1 a of thesubstrate 1.

As shown in FIG. 22, the symbol θ represents the angle formed by theinitial inclined surface 272P with respect to the initial bottom 271P.The angle θ is controllable within the range of 15° to 90° by changingthe ratio of the flow rate of CF₄ or N₂ to the total flow rate of theetching gas. If the ratios of the flow rates of CF₄ and N₂ to the totalflow rate of the etching gas are both 0%, the angle θ becomes 90°. Ifthe etching gas contains N₂ and the ratio of the flow rate of N₂ to thetotal flow rate of the etching gas is 8%, the angle θ becomes 45°. Ifthe ratio of the flow rate of N₂ to the total flow rate of the etchinggas is 20%, the angle θ becomes 20°. If the etching gas contains CF₄instead of N₂, the ratio of the flow rate of CF₄ to the total flow rateof the etching gas to form the same angle θ is approximately twice thatof the flow rate of N₂ to the total flow rate of the etching gas. Forexample, when the etching gas contains BCl₃, Cl₂, and CF₄, an angle θ of45° is obtained by setting the BCl₃ flow rate to 80 sccm, the Cl₂ flowrate to 15 sccm, and the CF₄ flow rate to 17 sccm. In this case, givenan etching time of 720 sec, the etching forms a groove of 1 μm in depthin the initial support body 27P. When the etching gas contains BCl₃,Cl₂, and N₂, the flow rates of BCl₃, Cl₂, and N₂ are set to 80, 15, and23 sccm, respectively. In this case, given an etching time of 400 sec,the etching forms a groove of 20° in angle θ and 0.5 μm in depth in theinitial support body 27P.

An example will be given of the conditions for the first etching stepother than the etching gas. This example employs an RIE system that usesa high frequency coil to produce plasma in a chamber by electromagneticinduction. The source power to the high frequency coil is 1200 W, with ahigh frequency bias power of 25 W and a chamber pressure of 0.3 Pa.

In the first etching step, the initial support body 27P is taper-etchedso that the initial inclined surface 272P forms an angle of, forexample, 45° with respect to the direction perpendicular to the topsurface 1 a of the substrate 1. The depth of the initial groove 27AP(the distance between the top surface of the initial support body 27Pand the initial bottom 271P) is 0.5 μm, for example. After the firstetching step, the not-shown initial sidewalls may be etched by RIE sothat the not-shown initial sidewalls become perpendicular to the topsurface 1 a of the substrate 1. In such a case, the initial inclinedsurface 272P may be covered with a photoresist mask.

FIG. 23 shows the next step. In this step, the etching mask 41 isremoved by, for example, stripping using an organic resist remover or byashing using an O₂-containing ashing gas.

FIG. 24 shows the next step. In this step, first, a second etching mask42 is formed on the top surface of the initial support body 27P. Theetching ask 42 is formed by patterning a photoresist layer byphotolithography, for example. The etching mask 42 has an opening thathas a shape corresponding to the planar shape of the waveguide 26. Theetching mask 42 covers a part of the initial support body 27P except thearea where the inclined surfaces 272 a and 272 b are to be formed lateras viewed in the direction perpendicular to the top surface 1 a of thesubstrate 1. In FIG. 24, the etching mask 42 has a side surface 42 athat is closer to the position where the medium facing surface 201 a isto be formed. As compared with the side surface 41 a of the etching mask41, the side surface 42 a is located farther from the position where themedium facing surface 201 a is to be formed.

FIG. 25 shows the next step. In this step, the initial support body 27Pis taper-etched by RIE using the etching mask 42. This step will bereferred to as a second etching step. The etching conditions employed inthe second etching step are the same as those employed in the firstetching step. FIG. 26 shows the state after the second etching step.

FIG. 26 shows a part of the stack after the initial support body 27P istaper-etched in the second etching step. As shown in FIG. 26, thetaper-etching of the initial support body 27P forms the groove 27A inthe initial support body 27P. This completes the bottom 271 and theinclined surfaces 272 a and 272 b, and thereby makes the initial supportbody 27P into the reflecting film support body 27. After the secondetching step, not-shown sidewalls of the groove 27A may be etched by RIEso that the sidewalls become perpendicular to the top surface 1 a of thesubstrate 1. In such a case, the inclined surfaces 272 a and 272 b andthe coupling surface 272 c may be covered with a photoresist mask.

In the second etching step, the initial support body 27P is taper-etchedby RIE using an etching gas that contains at least BCl₃, Cl₂ and CF₄ outof BCl₃, Cl₂, CF₄ and N₄ so that each of the inclined surfaces 272 a and272 b forms an angle of 45′ with respect to the direction perpendicularto the top surface 1 a of the substrate 1. The depth of the groove 27A(the distance between the top surface of the reflecting film supportbody 27 and the bottom 271) is 1 μm, for example.

Now, the second etching step will be described in more detail withreference to FIG. 24 to FIG. 26. In the second etching step, the initialsupport body 27P is taper-etched by utilizing the characteristic of RIEto be described below. When the initial support body 27P is etched byRIE using an etching gas that contains CF₄ or N₂, a sidewall-protectingfilm is formed on the sidewalls of the groove that is formed in theinitial support body 27P by the etching. The initial support body 27P isthus taper-etched in the portions near the etching mask 42. At the sametime, the initial support body 27P is perpendicularly etched in theportions away from the etching mask 42. Because of such a characteristicof RIE, in the second etching step, the initial bottom 271P of theinitial support body 27P and the portion of the initial support body 27Punder the initial inclined surface 272P are etched to form the bottom271 and the inclined surface 272 a. Meanwhile, the portion of theinitial support body 27P not etched in the first etching step is etchedto form the inclined surface 272 b.

In the second etching step, the inclined surfaces 272 a and 272 b may beformed so that the inclined surface 272 b is offset in a directionperpendicular to the inclined surface 272 a with respect to a virtualplane that includes the inclined surface 272 a. In such a case, thecoupling surface 272 c is formed so as to couple the inclined surfaces272 a and 272 b to each other.

As shown in FIG. 24 and FIG. 25, the distance between the side surface41 a of the etching mask 41 and the side surface 42 a of the etchingmask 42 will be represented by the symbol S1. The etching depth of thesecond etching step (the distance between the initial bottom 271P andthe bottom 271) will be represented by the symbol Dp. If the inclinedsurface 272 b is intended to form an angle of 45° with respect to thedirection perpendicular to the top surface 1 a of the substrate 1, S1 isdesigned to be equal or nearly equal to Dp. It is preferred that S1 be0.8 to 1.2 times Dp.

When the inclined surface 272 b forms an angle of 45° with respect tothe direction perpendicular to the top surface 1 a of the substrate 1and S1/Dp is 1, the inclined surfaces 272 a and 272 b ideally fall on anidentical plane without the formation of the coupling surface 272 c. Themanufacturing method for the heat-assisted magnetic recording head 200according to the embodiment also covers such a case.

Suppose that the inclined surface 272 b forms an angle of 45° withrespect to the direction perpendicular to the top surface 1 a of thesubstrate 1 and S1/Dp is other than 1. In such a case, the inclinedsurfaces 272 a and 272 b are formed so that the inclined surface 272 bis offset in the direction perpendicular to the inclined surface 272 awith respect to the virtual plane including the inclined surface 272 a,and there is formed the coupling surface 272 c. In particular, if S1/Dpis greater than 1, as shown in FIG. 26, the angle formed by the couplingsurface 272 c with respect to the direction perpendicular to the topsurface 1 a of the substrate 1 is greater than the angle formed by eachof the inclined surfaces 272 a and 272 b with respect to the directionperpendicular to the top surface 1 a of the substrate 1.

FIG. 27 shows the next step. In this step, the etching mask 42 isremoved by, for example, stripping using an organic resist remover or byashing using an O₂-containing ashing gas.

FIG. 28 shows the next step. In this step, a metal film 35P, which is tobecome the reflecting film 35 later, is formed over the inclinedsurfaces 272 a and 272 b and the coupling surface 272 c. The metal film35P is formed also on a part of the top surface of the reflecting filmsupport body 27 and a part of the bottom 271.

The steps after the step of FIG. 28 up to the formation of the waveguide26 and the internal mirror 30 will be described with reference to FIG.10. After the step of FIG. 28, a dielectric layer that is to become thewaveguide 26 later is initially formed over the entire top surface ofthe stack. Next, the dielectric layer and the metal film 35P arepolished by, for example, CMP, until the second layer 20B and thereflecting film support body 27 are exposed. This flattens the secondlayer 20B, the reflecting film support body 27 and the dielectric layerat the top. As a result, the dielectric layer left in the groove 27Amakes the waveguide 26. The metal film 35P left in the groove 27A makesthe reflecting film 35. The internal mirror 30 is thereby completed.

As has been described, in the heat-assisted magnetic recording head 200according to the present embodiment, the laser diode 202 is fixed to thetop surface 201 c of the slider 201. The laser light emitted from theemission part 222 a of the laser diode 202 is reflected by thereflecting surface of the reflecting part 203 a of the external mirror203, passes through the clad layer 29, the clad layer 24 and theinterposition layer 25, enters the waveguide 26 from the top surface 26c to reach the rear end face 26 b, where the laser light is reflected bythe internal mirror 30 so as to travel through the waveguide 26 towardthe medium facing surface 201 a (the front end face 26 a).

The internal mirror 30 includes the reflecting film support body 27 andthe reflecting film 35. The reflecting film support body 27 includes thefirst inclined surface 272 a and the second inclined surface 272 b. Withrespect to a virtual plane that includes the first inclined surface 272a, the second inclined surface 272 b is offset in the directionperpendicular to the first inclined surface 272 a. The reflecting film35 includes the first portion 351 located on the first inclined surface272 a, and the second portion 352 located on the second inclined surface272 b. The first portion 351 includes the first reflecting surface 351a, and the second portion 352 includes the second reflecting surface 352a. With respect to a virtual plane that includes the first reflectingsurface 351 a, the second reflecting surface 352 a is offset in thedirection perpendicular to the first reflecting surface 351 a.

The effects of the present embodiment will now be described. Adescription will initially be given of problems that are associated withthe formation of an internal mirror that has a single reflecting surfaceof large dimension in the depth direction. When taper-etching aninsulating layer such as the initial support body 27P of alumina, theetching rate is typically lower than when etching the insulating layerperpendicularly. Given the same etching depth, a photoresist etchingmask of greater thickness is therefore needed to taper-etch theinsulating layer than when etching the insulating layer perpendicularly.Thicker etching masks, however, can lose their shape more easily due toplasma-based reticulation and the like during etching.

Suppose, for example, that a 4-μm-thick photoresist etching mask isformed on the initial support body 27P, and the initial support body 27Pis taper-etched to form an inclined surface at an angle of 45° withrespect to the direction perpendicular to the top surface 1 a of thesubstrate 1. In such a case, the maximum etching depth up to which aplane inclined surface can be formed is around 1 μm. If the etching maskexceeds 4 μm in thickness, the etching mask will become deformed and itbecomes difficult to form a plane inclined surface. The maximum etchingdepth at which a plane inclined surface can be precisely formed by asingle taper-etching operation is thus 1 μm or so.

The laser light has a diameter of, for example, 1 to 2 μm when incidenton the reflecting surface of the internal mirror. Since the laser lightmay have a maximum displacement of 1 μm or so because of positioningerrors when fixing the laser diode 202 to the top surface 201 a of theslider 201, the reflecting surface needs to have a dimension of 2 to 4μm or so in the depth direction. To form a single reflecting surface ofsuch a dimension, a single, plane inclined surface having a dimension ofaround 2 to 4 μm in the depth direction needs to be formed in theinitial support body 27P. As discussed previously, however, it isdifficult to form a single, plane inclined surface of such a dimensionprecisely by a single taper-etching operation. If a single reflectingsurface is formed with a dimension as large as 2 to 4 μm in the depthdirection, the reflecting surface is no longer plane. This consequentlyreduces the amount of laser light that is reflected by the reflectingsurface and travels in a desired direction, and thus reduces the useefficiency of the laser light that is used to generate near-field light.

In the present embodiment, the reflecting film support body 27 includesthe first inclined surface 272 a and the second inclined surface 272 b.The first inclined surface 272 a and the second inclined surface 272 bcan be formed through a plurality of steps including two taper-etchingoperations, for example. As compared with the case of forming a single,plane inclined surface of large dimension, the first and second inclinedsurfaces 272 a and 272 b can be formed with higher precision.Consequently, according to the present embodiment, the first and secondreflecting surfaces 351 a and 352 a can also be formed with highprecision. The present embodiment thus makes it possible to prevent adrop in use efficiency of the laser light due to the internal mirror 30.

In the manufacturing method for the heat-assisted magnetic recordinghead 200 according to the present embodiment, the step of forming thereflecting film support body 27 includes the step of forming the initialsupport body 27P and the step of etching the initial support body 27P.The step of etching the initial support body 27P includes the first andsecond etching steps of taper-etching the initial support body 27P. Thefirst and second inclined surfaces 272 a and 272 b are completed afterthe second etching step. According to this manufacturing method, thefirst and second inclined surfaces 272 a and 272 b can be formed withhigher precision as compared with the case of forming a single, planeinclined surface of large dimension. Consequently, according to thepresent embodiment, the first and second reflecting surfaces 351 a and352 a can also be formed with high precision. The present embodimentthus makes it possible to prevent a drop in use efficiency of the laserlight due to the internal mirror 30.

Now, let us consider the dimension of the coupling surface 272 c in thedirection perpendicular to the medium facing surface 201 a (hereinafter,referred to as the width of the coupling surface 272 c) and thedimension of the coupling surface 353 a in the direction perpendicularto the medium facing surface 201 a (hereinafter, referred to as thewidth of the coupling surface 353 a). The width of the coupling surface353 a depends on the width of the coupling surface 272 c. As mentionedpreviously, the coupling surface 272 c is produced when S1/Dp is otherthan 1. If S1/Dp is greater than 1, the angle formed by the couplingsurface 272 c with respect to the direction perpendicular to the topsurface 1 a of the substrate 1 is greater than the angle formed by eachof the inclined surfaces 272 a and 272 b with respect to the directionperpendicular to the top surface 1 a of the substrate 1. Consequently,as shown in FIG. 10, the angle formed by the coupling surface 353 a withrespect to the direction perpendicular to the top surface 1 a of thesubstrate 1 is greater than the angle formed by each of the reflectingsurfaces 351 a and 352 a with respect to the direction perpendicular tothe top surface 1 a of the substrate 1. If S1/Dp is too large, the widthof the coupling surface 272 c becomes too large and the width of thecoupling surface 353 a also becomes too large. In this case, theproportion of light that is incident on the reflecting film 35 and isreflected off the coupling surface 353 a so as not to travel through thewaveguide 26 toward the medium facing surface 201 a becomes so high thatthe light use efficiency drops. In view of this, it is preferred thatS1/Dp be 1.2 or less. Situations where S1/Dp is less than 1 will bedealt with in a second embodiment.

Even when the etching masks 41 and 42 are intended to be formed so thatS1/Dp=1, the positions of the etching masks 41 and 42 may deviateslightly from the desired positions because of positioning errors whenforming the etching masks 41 and 42 by photolithography. Variations ofS1 ascribable to such positioning errors can be around 0.1 μm at most.The widths of the coupling surfaces 272 c and 353 a resulting from thepositioning errors can also be around 0.1 μm at most. Here, suppose thatthe reflecting surfaces 351 a and 352 a each have a dimension of 0.5 μmin the direction perpendicular to the medium facing surface 201 a, thecoupling surface 353 a has a width of 0.1 μm, and the laser lightincident on the reflecting film 35 has a diameter of 1 μm. In such acase, 90% of the laser light incident on the reflecting film 35 can bereflected by the reflecting surfaces 351 a and 352 a so as to travelthrough the waveguide 26 toward the medium facing surface 201 a (thefront end face 26 a).

Other effects of the present embodiment will now be described. In thepresent embodiment, the opposed portion 26 g of the outer surface of thewaveguide 26 is opposed to a part of the edge part 23 f of thenear-field light generating element 23 and its vicinity with theinterposition layer 25 interposed therebetween. In the presentembodiment, evanescent light occurs from the interposition layer 25based on the light propagating through the waveguide 26. Based on thisevanescent light, surface plasmons are excited on the near-field lightgenerating element 23. The surface plasmons then propagate to thenear-field light generating part 23 g, and the near-field lightgenerating part 23 g generates near-field light based on the surfaceplasmons. According to the present embodiment, it is possible toincrease the efficiency of conversion of the light propagating throughthe waveguide 26 into the near-field light, as compared with the casewhere a plasmon antenna is directly irradiated with laser light toproduce near-field light.

According to the present embodiment, it is possible suppress atemperature rise of the near-field light generating element 23 becausethe near-field light generating element 23 is not directly irradiatedwith the laser light propagating through the waveguide 26. In thepresent embodiment, the length H_(PA) of the near-field light generatingelement 23 in the direction perpendicular to the medium facing surface201 a is greater than the length T_(PA) of the first end face 23 a inthe direction perpendicular to the top surface 1 a of the substrate 1.Thus, the near-field light generating element 23 of the presentembodiment is greater in volume than a conventional plasmon antenna inwhich the length in the direction perpendicular to the medium facingsurface 201 a is smaller than the length in the direction perpendicularto the top surface 1 a of the substrate 1. This also contributes tosuppression of a temperature rise of the near-field light generatingelement 23. Consequently, according to the present embodiment, it ispossible to prevent the near-field light generating element 23 fromprotruding from the medium facing surface 201 a.

In the heat-assisted magnetic recording head 200 according to thepresent embodiment, the edge-emitting laser diode 202 is used as thelight source for emitting the light to be used for generating near-fieldlight. Typically, edge-emitting laser diodes have higher optical outputas compared with surface-emitting laser diodes.

The laser diode 202 is fixed to the slider 201 such that the bottomsurface 202 a lying at an end in the direction perpendicular to theplane of the active layer 222 faces the top surface 201 c of the slider201. The laser light emitted from the emission part 222 a of the laserdiode 202 is reflected by the external mirror 203 toward the waveguide26. The bottom surface 202 a of the laser diode 202 is parallel to theplane of the active layer 222 and has an area greater than that of theemitting end face 202 c. In the present embodiment, it is therefore easyto position the laser diode 202 with respect to the slider 201 with highprecision so that the optical axis of the laser light emitted from theemission part 222 a is parallel to the top surface 201 c of the slider201. Thus, according to the present embodiment, the optical axis of thelaser light emitted from the emission part 222 a can be prevented fromtilting with respect to a desired direction. According to the presentembodiment, it is therefore possible, while using the edge-emittinglaser diode 202 having a high optical output as the light source foremitting light to be used for generating near-field light, to align thelaser light with the waveguide easily as compared to the case where thelaser light emitted from the emission part 222 a is made incidentdirectly on the waveguide.

In the present embodiment, as shown in FIG. 1 and FIG. 2, the laserdiode 202, the external mirror 203, the internal mirror 30, and thewaveguide 26 are arranged so that the direction of travel of the laserlight L1 emitted from the emission part 222 a and the direction oftravel of the laser light L3 reflected by the internal mirror 30 areorthogonal to each other as viewed from above the top surface 201 c ofthe slider 201. According to the present embodiment, such arrangementallows the direction of polarization (the direction of oscillation ofthe electric field) of the laser light L3 reflected by the internalmirror 30 to be orthogonal to the direction of polarization of the laserlight L1 emitted from the emission part 222 a, as shown in FIG. 2.Consequently, the present embodiment makes it possible that thedirection of polarization of the laser light propagating through thewaveguide 26 is set to such a direction that surface plasmons of highintensity can be generated on the near-field light generating element23, i.e., the direction perpendicular to the opposed portion 26 g, whileusing a typical laser diode that emits laser light of TE mode as thelaser diode 202.

In the heat-assisted magnetic recording head 200 according to thepresent embodiment, the near-field light generating element 23 islocated farther from the top surface 1 a of the substrate 1 than is thesecond layer 20B of the magnetic pole 20, and the waveguide 26 islocated farther from the top surface 1 a of the substrate 1 than is thefirst layer 20A of the magnetic pole 20. The light emitted from thelaser diode 202 disposed above the waveguide 26 is reflected by theinternal mirror 30 so as to travel through the waveguide 26 toward themedium facing surface 201 a.

A case will now be considered where a near-field light generatingelement and a waveguide are located closer to the top surface 1 a of thesurface 1 than is the magnetic pole 20. In such a case, since themagnetic pole 20 lies above the near-field light generating element andthe waveguide, the optical path from the laser diode to the waveguidebecomes longer and the energy loss of the light increases if the laserdiode is disposed above the waveguide as in the present embodiment. Thelonger optical path from the laser diode to the waveguide also makes itharder to precisely position the laser diode and the waveguide, thusoften resulting in energy loss of the light due to misalignment betweenthe laser diode and the waveguide.

In contrast, the present embodiment allows shortening the optical pathfrom the laser diode 202 to the waveguide 26, thus making it possible toguide the light from the laser diode 202 to the opposed portion 26 g ofthe outer surface of the waveguide 26 through a shorter path. Accordingto the present embodiment, it is therefore possible to reduce the energyloss of the light. Furthermore, the present embodiment allows the laserdiode 202 and the waveguide 26 to be put close to each other, whichfacilitates precise positioning of the laser diode 202 and the waveguide26. Consequently, according to the present embodiment, it is possible toreduce the energy loss of the light resulting from misalignment betweenthe laser diode 202 and the waveguide 26.

In the present embodiment, the distance D1 between the bottom surface202 a and the emission part 222 a of the laser diode 202 is smaller thanthe distance D2 between the top surface 202 b and the emission part 222a of the laser diode 202. The laser light emitted from the emission part222 a of the laser diode 202 increases in diameter with increasingdistance from the emission part 222 a. If the distance D1 is greaterthan the distance D2, the path of the laser light from the emission part222 a to the internal mirror 30 becomes long, and accordingly, part ofthe laser light may fail to be incident on the internal mirror 30,thereby causing a drop in the amount of the laser light that propagatesthrough the waveguide 26. According to the present embodiment, incontrast, it is possible to make the path of the laser light from theemission part 222 a to the internal mirror 30 smaller than in the casewhere the distance D1 is greater than the distance D2. The presentembodiment thus allows the laser light to be incident on the internalmirror 30 with a smaller diameter. Consequently, according to thepresent embodiment, it is possible to prevent a drop in the amount ofthe laser light that propagates through the waveguide 26 due to thefailure of incidence of part of the laser light on the reflectingsurfaces 351 a and 352 a of the reflecting film 35 of the internalmirror 30.

In the present embodiment, the external mirror 203 can be formed by, forexample, molding a body out of an insulating material such as resin orglass, and forming a metal film on at least a part of the body that isto make the reflecting surface by vapor deposition, sputtering, or thelike. The part of the body to make the reflecting surface may bepolished before the formation of the metal film. It is thereby possibleto prevent the reflecting surface from being rounded at the portion nearthe border between the reflecting part 203 a and the to-be-fixed part203 c. This provides the following effect. As mentioned above, the laserlight emitted from the emission part 222 a increases in diameter withincreasing distance from the emission part 222 a. Thus, the longer thepath of the laser light from the emission part 222 a to the reflectingsurface of the reflecting part 203 a, the larger the diameter of thelaser light reflected by the reflecting surface. If, as described above,the part of the body to make the reflecting surface is polished beforeforming the metal film so as to prevent the reflecting surface frombeing rounded at the portion near the border between the reflecting part203 a and the to-be-fixed part 203 c, it becomes possible that the laserlight emitted from the emission part 222 a is reflected at a point onthe reflecting surface closer to the border between the reflecting part203 a and the to-be-fixed part 203 c. Consequently, the path of thelaser light from the emission part 222 a to the reflecting surface canbe reduced to prevent the diameter of the laser light reflected by thereflecting surface from being too large.

In the present embodiment, the interposition layer 25 having arefractive index lower than that of the waveguide 26 is disposed on thetop surface of the waveguide 26 on which the laser light is to beincident. Light that is incident on the interface between the waveguide26 and the interposition layer 25 from the side of the waveguide 26 atincident angles greater than or equal to the critical angle is thustotally reflected at the interface. Consequently, the laser light thatis emitted from the laser diode 202 and passes through the clad layer29, the clad layer 24 and the interposition layer 25 to enter thewaveguide 26 can be prevented from again passing through theinterposition layer 25, the clad layer 24 and the clad layer 29 toreturn to the laser diode 202. According to the present embodiment, itis therefore possible to increase the use efficiency of the laser lightand to prevent the laser diode 202 from being damaged by the laser lightthat returns to the laser diode 202.

From the foregoing, the present embodiment makes it possible to increasethe use efficiency of the light used for generating near-field light inthe heat-assisted magnetic recording head.

In the present embodiment, the initial support body 27P may betaper-etched more than twice with etching masks in respective differentpositions so as to form three or more inclined surfaces in thereflecting film support body 27. It follows that the reflecting film 35has three or more portions that are respectively located on the three ormore inclined surfaces of the reflecting film support body 27, and eachof the three or more portions has a reflecting surface. In such a case,the total size of the three or more reflecting surfaces of thereflecting film 35 can be made greater both in the directionperpendicular to the top surface 1 a of the substrate 1 and in thedirection perpendicular to the medium facing surface 201 a.

Modification Examples

First and second modification examples of the present embodiment willnow be described. FIG. 29 is a cross-sectional view showing theconfiguration of the heat-assisted magnetic recording head of the firstmodification example. The heat-assisted magnetic recording head of thefirst modification example is provided with a surface-emitting laserdiode 302 shown in FIG. 29, instead of the laser diode 202 and theexternal mirror 203 of the heat-assisted magnetic recording head shownin FIG. 1 to FIG. 7.

In the first modification example, the laser diode 302 is fixed to thetop surface 201 c of the slider 201. The laser diode 302 has an emissionpart 302 a on its bottom surface, and emits laser light downward fromthe emission part 302 a. The laser light emitted from the emission part302 a passes through the clad layer 29, the clad layer 24 and theinterposition layer 25, and enters the waveguide 26 from the top surface26 c to reach the rear end face 26 b, where the laser light is reflectedby the internal mirror 30 so as to travel through the waveguide 26toward the medium facing surface 201 a (the front end face 26 a).

The first modification example allows the laser light emitted from theemission part 302 a to be made incident directly on the clad layer 29without reflection by the external mirror. The first modificationexample thus allows shortening the optical path from the laser diode 302to the waveguide 26, and accordingly makes it possible to guide thelight from the laser diode 302 to the opposed portion 26 g of the outersurface of the waveguide 26 through a shorter path. According to thefirst modification example, it is therefore possible to reduce theenergy loss of the light. Furthermore, the first modification exampleallows the laser diode 302 and the waveguide 26 to be put close to eachother, which facilitates precise positioning of the laser diode 302 andthe waveguide 26. Consequently, according to the first modificationexample, it is possible to reduce the energy loss of the light resultingfrom misalignment between the laser diode 302 and the waveguide 26.

The second modification example of the present embodiment will now bedescribed. FIG. 30 is a plan view showing a part of the waveguide 26 andthe near-field light generating element 23 of the second modificationexample. FIG. 31 is a perspective view of the near-field lightgenerating element 23 shown in FIG. 30. In the near-field lightgenerating element 23 of the second modification example, the sidesurfaces 23 d and 23 e have their respective portions that decrease indistance from each other in the track width direction with decreasingdistance to the medium facing surface 201 a. The corner portion betweenthe side surface 23 d and the second end face 23 b and the cornerportion between the side surface 23 e and the second end face 23 b areboth rounded. In the second modification example, in particular, theside surfaces 23 d and 23 e excluding the above-mentioned two cornerportions decrease in distance from each other in the track widthdirection with decreasing distance to the medium facing surface 201 a.

The top surface 23 c has a first edge 223 a that is located at the topend of the first end face 23 a, a second edge 223 b that is located atthe top end of the second end face 23 b, a third edge 223 d that islocated at the top end of the side surface 23 d, and a fourth edge 223 ethat is located at the top end of the side surface 23 e. The third edge223 d and the fourth edge 223 e have their respective portions thatdecrease in distance from each other in a direction parallel to thefirst edge 223 a with decreasing distance to the first edge 223 a. Thecorner portion between the second edge 223 b and the third edge 223 dand the corner portion between the second edge 223 b and the fourth edge223 e are both rounded. In the second modification example, inparticular, the third edge 223 d and the fourth edge 223 e excluding theabove-mentioned two corner portions decrease in distance from each otherin the direction parallel to the first edge 223 a with decreasingdistance to the first edge 223 a.

The near-field light generating element 23 of the second modificationexample has a bottom surface 23 h that is closer to the top surface 1 aof the substrate 1. A part of the top surface 26 c of the waveguide 26is opposed to a part of the bottom surface 23 h of the near-field lightgenerating element 23 with the interposition layer 25 interposedtherebetween. FIG. 30 shows an example in which the front end face 26 aof the waveguide 26 is located away from the medium facing surface 201a. However, the front end face 26 a may be located in the medium facingsurface 201 a.

As shown in FIG. 31, the near-field light generating element 23 of thesecond modification example is configured so that an area near the firstend face 23 a (hereinafter, referred to as front end vicinity area) hasa bottom end that gets farther from the top surface 1 a of the substrate1 with decreasing distance to the first end face 23 a. Only in the frontend vicinity area of the near-field light generating element 23, each ofthe side surfaces 23 d and 23 e includes an upper part and a lower partthat are continuous with each other, and the angle formed between thelower part of the side surface 23 d and the lower part of the sidesurface 23 e is smaller than that formed between the upper part of theside surface 23 d and the upper part of the side surface 23 e. In thearea other than the front end vicinity area of the near-field lightgenerating element 23, the side surfaces 23 d and 23 e are each plane oralmost plane in shape.

The first end face 23 a includes: a first side 123 d that is located atan end of the first side surface 23 d; a second side 123 e that islocated at an end of the second side surface 23 e; a third side 123 cthat is located at an end of the top surface 23 c; and a pointed tip 123g that is formed by contact of the first side 123 d and the second side123 e with each other and constitutes the near-field light generatingpart 23 g. Specifically, the near-field light generating part 23 grefers to the pointed tip 123 g and its vicinity in the end face 23 a.

The first side 123 d includes an upper part and a lower part that arecontinuous with each other. The second side 123 e includes an upper partand a lower part that are continuous with each other. The angle formedbetween the lower part of the first side 123 d and the lower part of thesecond side 123 e is smaller than the angle formed between the upperpart of the first side 123 d and the upper part of the second side 123e.

As shown in FIG. 30, the length of the near-field light generatingelement 23 in the direction perpendicular to the medium facing surface201 a will be denoted by the symbol H_(PA); the width of the first endface 23 a at its top edge will be denoted by the symbol W_(PA); and themaximum width of the near-field light generating element 23 in the trackwidth direction (the X direction) will be denoted by the symbol WB_(PA).As shown in FIG. 31, the length of the first end face 23 a in thedirection perpendicular to the top surface 1 a of the substrate 1 willbe denoted by the symbol T_(PA). The length H_(PA) of the near-fieldlight generating element 23 in the direction perpendicular to the mediumfacing surface 201 a is greater than the length T_(PA) of the first endface 23 a in the direction perpendicular to the top surface 1 a of thesubstrate 1. W_(PA) falls within the range of 50 to 350 nm, for example.T_(PA) falls within the range of 60 to 350 nm, for example. H_(PA) fallswithin the range of 0.25 to 2.5 μm, for example. WB_(PA) falls withinthe range of 0.25 to 2.5 μm, for example.

The second modification example allows an increase in area of theopposed portion of the waveguide 26 opposed to a part of the couplingpart (a part of the bottom surface 23 h) of the outer surface of thenear-field light generating element 23. Consequently, it is possible toexcite more surface plasmons on the coupling part (the bottom surface 23h) of the near-field light generating element 23. According to thesecond modification example, in the near-field light generating element23, the corner portion between the side surface 23 d and the second endface 23 b and the corner portion between the side surface 23 e and thesecond end face 23 b are both rounded. This can prevent near-field lightfrom occurring from these corner portions. In the second modificationexample, the side surfaces 23 d and 23 e of the near-field lightgenerating element 23, excluding the foregoing two corner portions,decrease in distance from each other in the track width direction withdecreasing distance to the medium facing surface 201 a. Thisconfiguration can concentrate surface plasmons excited on the bottomsurface 23 h while the surface plasmons propagate to the near-fieldlight generating part 23 g. According to the second modificationexample, it is therefore possible to concentrate more surface plasmonsat the near-field light generating part 23 g of pointed shape.

Second Embodiment

A second embodiment of the present invention will now be described. FIG.32 is a cross-sectional view showing the internal mirror and itsvicinity in the heat-assisted magnetic recording head according to thepresent embodiment.

In the internal mirror 30 of the present embodiment, as shown in FIG.32, the angle formed by the coupling surface 272 c with respect to thedirection perpendicular to the top surface 1 a of the substrate 1 issmaller than the angle formed by each of the inclined surfaces 272 a and272 b with respect to the direction perpendicular to the top surface 1 aof the substrate 1. The angle formed by the coupling surface 353 a withrespect to the direction perpendicular to the top surface 1 a of thesubstrate 1 is smaller than the angle formed by each of the reflectingsurfaces 351 a and 352 a with respect to the direction perpendicular tothe top surface 1 a of the substrate 1.

A description will now be given of a manufacturing method for theheat-assisted magnetic recording head according to the presentembodiment. The manufacturing method for the heat-assisted magneticrecording head according to the present embodiment includes the samesteps as those of the manufacturing method for the heat-assistedmagnetic recording head according the first embodiment up to the step ofremoving the etching mask 41 (FIG. 23).

FIG. 33 shows the step after the removal of the etching mask 41. FIG. 33shows a cross section of a part of a stack of layers in the process ofmanufacturing the heat-assisted magnetic recording head, the crosssection being perpendicular to the medium facing surface 201 a and thetop surface 1 a of the substrate 1. In FIG. 33, the portions lyingcloser to the substrate 1 than the initial support body 27P are omitted.In this step, the etching mask 42 is initially formed on the top surfaceof the initial support body 27P as in the step shown in FIG. 24. In thepresent embodiment, the side surface 42 a of the etching mask 42 islocated at a position different from that in the first embodiment. Thesubsequent steps are the same as those of the first embodiment.

In the present embodiment, the etching mask 42 is arranged so that theinclined surface 272 b forms an angle of 45′ with respect to thedirection perpendicular to the top surface 1 a of the substrate 1, andS1/Dp defined in the first embodiment is smaller than 1. If S1/Dp issmaller than 1, as shown in FIG. 32, the angle formed by the couplingsurface 272 c with respect to the direction perpendicular to the topsurface 1 a of the substrate 1 becomes smaller than the angle formed byeach of the inclined surfaces 272 a and 272 b with respect to thedirection perpendicular to the top surface 1 a of the substrate 1.Consequently, the angle formed by the coupling surface 353 a withrespect to the direction perpendicular to the top surface 1 a of thesubstrate 1 becomes smaller than the angle formed by each of thereflecting surfaces 351 a and 352 a with respect to the directionperpendicular to the top surface 1 a of the substrate 1. According tothe present embodiment, it is therefore possible to prevent the laserlight incident on the reflecting film 35 from being reflected in part bythe coupling surface 353 a so as to return to the laser diode 202. Thelaser diode 202 can thus be prevented from being damaged by the laserlight that returns to the laser diode 202.

If S1/Dp is too small, the distance between the reflecting surfaces 351a and 352 a in the direction perpendicular to the top surface 1 a of thesubstrate 1 becomes too large, and the laser light reflected by thereflecting film 35 thus has too large a diameter. In this point of view,it is preferred that S1/Dp be 0.8 or above.

The remainder of configuration, function and effects of the presentembodiment are similar to those of the first embodiment.

Third Embodiment

A third embodiment of the present invention will now be described. FIG.34 is a cross-sectional view showing the internal mirror and itsvicinity in the heat-assisted magnetic recording head according to thepresent embodiment. The reflecting film support body 27 of the presentembodiment includes a first layer 127A, and a second layer 127B lying onthe first layer 127A. The first layer 127A has a groove 127A1 that opensin the top surface. The groove 127A1 has the bottom 271 and the firstinclined surface 272 a. The second layer 127B has a penetrating opening127B1. The opening 127B1 has the second inclined surface 272 b. Thegroove 127A1 and the opening 127B2 constitute the groove 27A. The groove27A of the present embodiment has a coupling surface 272 d, which is apart of the bottom surface of the second layer 127B, instead of thecoupling surface 272 c of the second embodiment.

The inclined surfaces 272 a and 272 b of the present embodiment arearranged so as to overlap each other as viewed in the directionperpendicular to the top surface 1 a of the substrate 1. That is, in thepresent embodiment, the front end 272 b 1 of the inclined surface 272 bis located closer to the medium facing surface 201 a than is the rearend 272 a 2 of the inclined surface 272 a. The coupling surface 272 dfaces toward the top surface 1 a of the substrate 1, and lies inparallel with the top surface 1 a of the substrate 1.

The reflecting film 35 of the present embodiment has the first portion351 located on the first inclined surface 272 a, the second portion 352located on the second inclined surface 272 b, and the portion 354located on the bottom 271 of the groove 27A and coupled to the firstportion 351. The reflecting film 35 does not have any coupling portionthat couples the first portion 351 to the second portion 352, however.The first portion 351 and the second portion 352 are separated from eachother. The reflecting film 35 need not have the portion 354. Thereflecting surfaces 351 a and 352 a of the present embodiment arearranged so as to overlap each other as seen in the directionperpendicular to the top surface 1 a of the substrate 1. That is, in thepresent embodiment, the front end 352 a 1 of the reflecting surface 352a is located closer to the medium facing surface 201 a than is the rearend 351 a 2 of the reflecting surface 351 a.

The waveguide 26 of the present embodiment includes a first layer 126Athat is closer to the top surface 1 a of the substrate 1 and a secondlayer 126B that is farther from the top surface 1 a of the substrate 1.At least part of the first layer 126A is accommodated in the groove127A1. At least part of the second layer 126B is accommodated in theopening 127B1.

Although not shown in the drawings, the second layer 20B of the magneticpole 20 of the present embodiment includes a first portion that iscloser to the top surface 1 a of the substrate 1 and a second portionthat is farther from the top surface 1 a of the substrate 1.

A manufacturing method for the heat-assisted magnetic recording headaccording to the present embodiment will now be described. Themanufacturing method for the heat-assisted magnetic recording headaccording to the present embodiment includes the same steps as those ofthe manufacturing method for the heat-assisted magnetic recording headaccording to first embodiment up to the step of flattening the firstlayer 20A of the magnetic pole 20 and the nonmagnetic layer 21 at thetop (FIG. 14A and FIG. 14B).

FIG. 35 shows the step after the first layer 20A of the magnetic pole 20and the nonmagnetic layer 21 are flattened at the top. FIG. 35 shows across section of a part of a stack of layers in the process ofmanufacturing the heat-assisted magnetic recording head, the crosssection being perpendicular to the medium facing surface 201 a and thetop surface 1 a of the substrate 1. In FIG. 35, the portions lyingcloser to the substrate 1 than the first layer 127A of the reflectingfilm support body 27 are omitted. In this step, although not shown, thefirst portion of the second layer 2013 is initially formed on the firstlayer 20A by frame plating, for example. Next, an initial first layer,which is intended to undergo the formation of the inclined surface 272 atherein later to thereby become the first layer 127A, is formed over theentire top surface of the stack. The initial first layer is thenpolished by, for example, CMP until the first portion of the secondlayer 20B is exposed. This flattens the first portion of the secondlayer 20B and the initial first layer at the top.

Next, a first etching mask 43 is formed on the initial first layer. Theetching mask 43 is formed by patterning a photoresist layer byphotolithography, for example. The etching mask 43 has an opening thathas a shape corresponding to the planar shape of the first layer 126A ofthe waveguide 26. The etching mask 43 covers a part of the initial firstlayer except the area where the inclined surface 272 a is to be formedlater as viewed in the direction perpendicular to the top surface 1 a ofthe substrate 1.

Using the etching mask 43, the initial first layer is then taper-etchedby RIE. This step will be referred to as a first etching step. Theetching conditions employed in this step are the same as those employedin the first etching step of the first embodiment. As shown in FIG. 35,the etching of the initial first layer forms the groove 127A1 in theinitial first layer. This also forms the bottom 271 and the inclinedsurface 272 a, so that the initial first layer becomes the first layer127A.

FIG. 36 shows the next step. FIG. 36 shows a cross section of a part ofa stack of layers in the process of manufacturing the heat-assistedmagnetic recording head, the cross section being perpendicular to themedium facing surface 201 a and the top surface 1 a of the substrate 1.In FIG. 36, the portions lying closer to the substrate 1 than the firstlayer 127A of the reflecting film support body 27 are omitted. In thisstep, first, the etching mask 43 is removed. Next, a metal film that isto be made into the first portion 351 and the portion 354 of thereflecting film 35 later is formed over the inclined surface 272 a and apart of the bottom 271. The metal film is formed also on a part of thetop surface of the first layer 127A. Next, a dielectric layer that is tobecome the first layer 126A of the waveguide 26 later is formed over theentire top surface of the stack. The dielectric layer and the metal filmare then polished by, for example, CMP, until the first portion of thesecond layer 20B and the first layer 127A of the reflecting film supportbody 27 are exposed. This flattens the first portion of the second layer20B, the first layer 127A, and the dielectric layer at the top. As aresult, the dielectric layer left in the groove 127A1 makes the firstlayer 126A of the waveguide 26. The metal film left in the groove 127A1makes the first portion 351 and the portion 354 of the reflecting film35.

Next, although not shown in the drawings, the second portion of thesecond layer 20B is formed on the first portion of the second layer 20Bby frame plating, for example. Next, an initial second layer, which isintended to undergo the formation of the inclined surface 272 b thereinlater to thereby become the second layer 127B, is formed over the entiretop surface of the stack. The initial second layer is then polished by,for example, CMP, until the second portion of the second layer 20B isexposed. This flattens the second portion of the second layer 20B andthe initial second layer at the top.

Next, a second etching mask 44 is formed on the top surface of theinitial second layer. The etching mask 44 is formed by patterning aphotoresist layer by photolithography, for example. The etching mask 44has an opening that has a shape corresponding to the planar shape of thesecond layer 126B of the waveguide 26. The etching mask 44 covers a partof the initial second layer except the area where the inclined surfaces272 a and 272 b are to be formed later as viewed in the directionperpendicular to the top surface 1 a of the substrate 1. Using theetching mask 44, the initial second layer is then taper-etched by RIE.This step will be referred to as a second etching step. The etchingconditions employed in this step are the same as those employed in thesecond etching step of the first embodiment. As shown in FIG. 36, theetching of the initial second layer forms the opening 127B1 in theinitial second layer. This also forms the inclined surface 272 b, sothat the initial second layer becomes the second layer 127B.

The steps after the step of FIG. 36 up to the formation of the secondlayer 126B of the waveguide 26 and the second portion 352 of thereflecting film 35 will be described with reference to FIG. 34. In thisstep, first, the etching mask 44 is removed. Next, a metal film that isto become the second portion 352 of the reflecting film 35 later isformed on the inclined surface 272 b. The metal film is formed also on apart of the top surface of the second layer 127B. Next, a dielectriclayer that is to become the second layer 126B of the waveguide 26 lateris formed over the entire top surface of the stack. The dielectric layerand the metal film are then polished by, for example, CMP until thesecond portion of the second layer 20B and the second layer 127B areexposed. This flattens the second portion of the second layer 20B, thesecond layer 127B, and the dielectric layer at the top. As a result, thedielectric layer left in the opening 127B1 makes the second layer 126Bof the waveguide 26. The metal film left in the opening 127B1 makes thesecond portion 352 of the reflecting film 35. The subsequent steps arethe same as those of the first embodiment.

In the present embodiment, the reflecting surfaces 351 a and 352 a arearranged so as to overlap each other as seen in the directionperpendicular to the top surface 1 a of the substrate 1. Consequently,according to the present embodiment, it is possible to prevent part ofthe laser light incident on the reflecting film 35 from returning to thelaser diode 202. The laser diode 202 can thus be prevented from beingdamaged by the laser light that returns to the laser diode 202.

In the present embodiment, the reflecting film support body 27 mayinclude three or more stacked layers having respective inclinedsurfaces, and the reflecting film 35 may include three or more portionslocated on the respective inclined surfaces of the three or more layersof the reflecting film support body 27. The respective inclined surfacesof the layers of the reflecting film support body 27 are formed bytaper-etching. In such a case, the total size of three or morereflecting surfaces of the reflecting film 35 can be made greater bothin the direction perpendicular to the top surface 1 a of the substrate 1and in the direction perpendicular to the medium facing surface 201 a.

The remainder of configuration, function and effects of the presentembodiment are similar to those of the second embodiment.

It should be appreciated that the present invention is not limited tothe foregoing embodiments, and various modifications may be madethereto. For example, in the first to third embodiments, the laser diode202, the external mirror 203, the internal mirror 30 and the waveguide26 may be arranged so that the direction of travel of the laser lightemitted from the emission part 222 a of the laser diode 202 and thedirection of travel of the laser light reflected by the internal mirror30 are parallel to each other.

In the present invention, the magnetic pole 20 need not include thesecond layer 20B. The waveguide 26 may be located farther from the topsurface 1 a of the substrate 1 than is the near-field light generatingelement 23.

In the present invention, the near-field light generating element 23 mayhave a shape other than the shapes shown in FIG. 9 and FIG. 31.

It is apparent that the present invention can be carried out in variousforms and modifications in the light of the foregoing descriptions.Accordingly, within the scope of the following claims and equivalentsthereof, the present invention can be carried out in forms other thanthe foregoing most preferable embodiments.

1. A heat-assisted magnetic recording head comprising: a medium facingsurface that faces a recording medium; a magnetic pole that has an endface located in the medium facing surface, for producing a recordingmagnetic field for recording data on the recording medium; a waveguidethat allows light to propagate therethrough; a near-field lightgenerating element having a near-field light generating part located inthe medium facing surface, a surface plasmon being excited based on thelight propagating through the waveguide, the surface plasmon propagatingto the near-field light generating part, the near-field light generatingpart generating near-field light based on the surface plasmon; aninternal mirror; and a substrate having a top surface, wherein: themagnetic pole, the waveguide, the near-field light generating element,and the internal mirror are located above the top surface of thesubstrate; the internal mirror includes a reflecting film support body,and a reflecting film supported by the reflecting film support body, theinternal mirror reflecting light that comes from above the waveguide sothat the reflected light travels through the waveguide toward the mediumfacing surface; the reflecting film support body includes a firstinclined surface and a second inclined surface, each of the first andsecond inclined surfaces having a front end and a rear end; the rear endof the first inclined surface is located farther from the medium facingsurface and farther from the top surface of the substrate than is thefront end of the first inclined surface; the front end of the secondinclined surface is located farther from the medium facing surface andfarther from the top surface of the substrate than is the front end ofthe first inclined surface; the rear end of the second inclined surfaceis located farther from the medium facing surface and farther from thetop surface of the substrate than are the rear end of the first inclinedsurface and the front end of the second inclined surface; with respectto a virtual plane that includes the first inclined surface, the secondinclined surface is offset in a direction perpendicular to the firstinclined surface; the reflecting film includes a first portion locatedon the first inclined surface, and a second portion located on thesecond inclined surface; the first portion includes a first reflectingsurface having a front end and a rear end; the second portion includes asecond reflecting surface having a front end and a rear end; the rearend of the first reflecting surface is located farther from the mediumfacing surface and farther from the top surface of the substrate than isthe front end of the first reflecting surface; the front end of thesecond reflecting surface is located farther from the medium facingsurface and farther from the top surface of the substrate than is thefront end of the first reflecting surface; the rear end of the secondreflecting surface is located farther from the medium facing surface andfarther from the top surface of the substrate than are the rear end ofthe first reflecting surface and the front end of the second reflectingsurface; and with respect to a virtual plane that includes the firstreflecting surface, the second reflecting surface is offset in adirection perpendicular to the first reflecting surface.
 2. Theheat-assisted magnetic recording head according to claim 1, wherein eachof the first and second reflecting surfaces forms an angle of 45° withrespect to a direction perpendicular to the top surface of thesubstrate.
 3. The heat-assisted magnetic recording head according toclaim 1, wherein the first and second inclined surfaces are arranged soas not to overlap each other as seen in a direction perpendicular to thetop surface of the substrate.
 4. The heat-assisted magnetic recordinghead according to claim 1, wherein the reflecting film further includesa coupling portion that couples the first portion to the second portion,the coupling portion including a coupling surface that couples the firstreflecting surface to the second reflecting surface.
 5. Theheat-assisted magnetic recording head according to claim 4, wherein anangle formed by the coupling surface with respect to a directionperpendicular to the top surface of the substrate is greater than anangle formed by each of the first and second reflecting surfaces withrespect to the direction perpendicular to the top surface of thesubstrate.
 6. The heat-assisted magnetic recording head according toclaim 4, wherein an angle formed by the coupling surface with respect toa direction perpendicular to the top surface of the substrate is smallerthan an angle formed by each of the first and second reflecting surfaceswith respect to the direction perpendicular to the top surface of thesubstrate.
 7. The heat-assisted magnetic recording head according toclaim 1, wherein the first and second inclined surfaces are arranged soas to overlap each other as viewed in a direction perpendicular to thetop surface of the substrate.
 8. The heat-assisted magnetic recordinghead according to claim 1, wherein: the near-field light generatingelement has an outer surface, the outer surface including: a first endface that is located in the medium facing surface; a second end facethat is farther from the medium facing surface; and a coupling part thatcouples the first end face to the second end face, the first end faceincluding the near-field light generating part; a length of thenear-field light generating element in a direction perpendicular to themedium facing surface is greater than a length of the first end face ina direction perpendicular to the top surface of the substrate; and thewaveguide has an outer surface including an opposed portion that isopposed to a part of the coupling part.
 9. The heat-assisted magneticrecording head according to claim 8, wherein: the outer surface of thewaveguide includes a front end face that is closer to the medium facingsurface, a rear end face that is farther from the medium facing surface,and a top surface that is farther from the top surface of the substrate;the rear end face is in contact with the first and second reflectingsurfaces; and the light that comes from above the waveguide is reflectedby the first and second reflecting surfaces after entering the waveguidefrom the top surface of the waveguide.
 10. The heat-assisted magneticrecording head according to claim 1, further comprising a laser diodethat emits the light to be reflected by the internal mirror.